Curse of Therianthropy. A humanoid or fey creature can be afflicted with the curse of therianthropy after being wounded by a therianthrope, or if one or both of its parents are therianthropes. A remove curse spell can rid an afflicted therianthrope of the curse, this must be done before the first full moon. Before the second and the third full moon the curse can be removed with a Remove Curse costing 350gp (needs 350gp in silver and wolfsbane as a special component.) Once a player becomes a hybrid the only way for them to be freed is via the wish spell. A natural born therianthrope can be freed of the curse only with a wish. A player cannot remove the curse without the consent of the person afflicted by the curse. Players cannot have their characters start with therianthropy.
A therianthrope can either resist its curse or embrace it. By resisting the curse, a therianthrope lives its life as it always has, burying deep the bestial urges raging inside it. However, when the full moon rises, the curse becomes too strong to resist, transforming the individual into its beast form. When the moon wanes, the beast within can be controlled once again. If the cursed creature is unaware of its condition, it might not remember the events of its transformation, though those memories often haunt a therianthrope as bloody dreams.
Some individuals see little point in fighting the curse and accept what they are. With time and experience, they learn to master their shape changing ability and can assume beast form or hybrid form at will. Most therianthropes that embrace their bestial natures succumb to bloodlust, becoming evil, opportunistic creatures that prey on the weak.
A character who becomes a therianthrope retains his or her statistics except as specified by the therianthrope type. The character gains the therianthrope's speeds in non-humanoid/fey form, as well as the senses, damage immunities, traits, and actions that don't involve equipment. The character is proficient with the therianthrope's natural attacks, such as its bite or claws, the attack and damage rolls of which are based on what the specific therianthrope uses for their natural attacks.
A cursed PC gains the appropriate stat increase depending on which form of therianthropy they are afflicted with in their normal form if their score isn't already higher, and a +1 to AC while in beast or hybrid form. While in their therianthropic form a character can only use the natural attacks given to them by the form (ie bite or claws).
The Bloodhunter Subclass's rules replaces these if one is an Order of the Lycan Bloodhunter.
A non-therianthrope humanoid or fey hit by an attack that carries the curse of therianthropy must succeed a Constitution Saving Throw (DC 8 + Therianthrope's Proficiency bonus + Therianthrope's Constitution modifier) or be cursed with Therianthropy of the Therianthrope's type.
Physical Changes. Physically weak characters might gain increases to their stats while cursed with therianthropy. Different types of curses will have different effects on stats. PCs might also gain bonuses to Perception and Stealth as the curse heightens their instincts.
Bloodlust. When a single attack deals 20 or more damage to you, you must make a Wisdom check. The DC equals 15 or half the damage you take, whichever number is higher, on a failure you transform into your beast form. While transformed you move directly towards the nearest creature and must use the attack action against that creature. If you have extra attack you must use your extra attack(s). If there is more than one creature within range you roll a dice to determine your target at random. If you are under an effect that prevents you from concentrating (like the barbarian's Rage feature), you automatically fail this saving throw. You recognise all creatures as enemies unless they are a transformed Therianthrope of the same species. While below half your maximum hit points you make this roll at disadvantage. You automatically revert to your humanoid or fey form after 1 hour or if you fall unconscious or drop to 0 hit points. If you revert to humanoid or fey form by having your hit points reduced to zero, or due to spending a full hour in beast form, you gain 1 level of exhaustion.
At the start of each of your turns while transformed in this way you may make a DC 15 WIS check to regain control and revert to your original form.
The moon cycles of Embris are 1:1 with the real world. This is for the sake of simplicity as well as it would take an adequate amount of time to master the new changes that come with therianthropy. The moon cycles are as follows:
1st Full Moon. You can willingly turn into your animal form, but you still lack control over what you do. Removing the curse becomes more difficult and requires casting Remove Curse and 350gp of powdered silver and wolfsbane. (total cost of 500gp from an NPC for either)
2nd Full Moon. You gain better control of your animal form. Whenever you willingly transform into your animal form you keep control of what you do.
3rd Full Moon. You learn how to become a hybrid of the two forms. If you embrace the curse by transforming into a hybrid, the therianthropy becomes a part of you and it will take a Wish or similar magic to remove the curse.
If you are able to cast spells, you can't cast them or concentrate on them while transformed. You cannot activate class features (Such as divine smite, sneak attack or action surge) while transformed but you gain the benefit of any passive class features or features that were activated before transformation. You choose whether your equipment falls to the ground in your space, merges into your new form, or is worn by it. Worn equipment functions as normal, but the DM decides whether it is practical for the new form to wear a piece of equipment, based on the creature's shape and size. Your equipment doesn't change size or shape to match the new form, and any equipment that the new form can't wear must either fall to the ground or merge with it. Equipment that merges with the form has no effect until you leave the form.
Bloodlust. When a single attack deals 20 or more damage to you, you must make a Wisdom check. The DC equals 15 or half the damage you take, whichever number is higher, on a failure you transform. While transformed you move directly towards the nearest creature and must use the attack action against that creature. If you have extra attack you must use your extra attack(s). If there is more than one creature within range you roll a dice to determine your target at random. If you are under an effect that prevents you from concentrating (like the barbarian's Rage feature), you automatically fail this saving throw. You recognise all creatures as enemies unless they are a transformed Therianthrope of the same species. While below half your maximum hit points you make this roll at disadvantage. You automatically revert to your normal form after 1 hour or if you fall unconscious or drop to 0 hit points. If you revert to humanoid or fey form by having your hit points reduced to zero, or due to spending a full hour in beast form, you gain 1 level of exhaustion.
At the start of each of your turns while transformed in this way you may make a DC 15 WIS check to regain control and revert to your original form.
Going Beast. It takes a bonus action to shift into or out of your hybrid form or beast form. You can use this feature a number of times equal to your proficiency bonus, regaining all uses on a long rest. This feature lasts for 1 hour.
Beast Hide. You have +1 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons.
Weapon Handling. You are still capable of wielding your held weapons.
Shapechanger. You have access to your were-forms shapechanger features.
Werebat
Stats. Your Dexterity becomes 13, unless it is 13 or higher already, and your Constitution becomes 10, unless it is 10 or higher already.
Skills. You gain proficiency with Perception and Stealth.
Keen Sound. In all forms, you have advantage on Wisdom (Perception) checks that rely on sound.
Nimbleness. While in beast form, you have the ability to move through any Medium or larger creature.
Echolocation. While in hybrid form, you have 10ft of blindsight.
Shapechanger. Your beast-humanoid hybrid is a half-bat. Your beast form is a tiny bat. While in either of these forms, you gain access to your bite.
Beast Hide. While in Beast or Hybrid form you gain +1 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons.
Bite. You can use your action to make a special attack with your unarmed strike using your teeth. On a hit, the target takes piercing damage equal to 1d4 + your Dexterity modifier. If you have the Sneak Attack feature, you can apply it to this attack. If the target is a humanoid or fey, it must make a Constitution saving throw or be cursed with werebat therianthropy. The DC of this saving throw is 8 + your proficiency bonus + your Constitution modifier.
Werebear
Stats. Your Strength becomes 14, unless it is 14 or higher already, and your Constitution becomes 12, unless it is 12 or higher already.
Skills. In all forms, you gain Expertise in Perception when making checks that rely on smell.
Shapechanger. Your beast-humanoid hybrid is a half-bear. Your beast form is a Large bear. While in either of these forms, you gain access to your Bite and Claws. In addition, while in your hybrid form or beast form, your walking speed increases by 10 feet, and you gain a climbing speed of 30 feet.
Beast Hide. While in Beast or Hybrid form you gain +1 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons.
Bite. You can use your action to make a special attack with your unarmed strike using your teeth. On a hit, the target takes piercing damage equal to 1d10 + your Strength modifier. If the target is a humanoid or fey, it must make a Constitution saving throw or be cursed with werebear therianthropy. The DC of this saving throw is 8 + your proficiency bonus + your Constitution modifier.
Claws. Your claws are natural weapons, which you can use to make unarmed strikes. If you hit with them, you deal slashing damage equal to 1d8 + your Strength modifier, instead of the bludgeoning damage normal for an unarmed strike.
Wereboar
Stats. Your Strength becomes 14, unless it is 14 or higher already, and your Constitution becomes 12, unless it is 12 or higher already.
Skills. In all forms, you gain Proficiency in Perception.
Relentless. When you are reduced to 0 hit points but not killed outright, you can drop to 1 hit point instead. You can't use this feature again until you finish a short or long rest.
Shapechanger. Your beast-humanoid hybrid is a half-boar. Your beast form is a medium boar. While in either of these forms, you gain access to your Tusks and your Charge. In addition, while in your hybrid form or beast form, your walking speed increases by 10 feet.
Beast Hide. While in Beast or Hybrid form you gain +1 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons.
Charge. While in beast or hybrid form, if you move at least 15 feet straight toward a target and then hit it with your tusks on the same turn, the target takes an extra 2d6 slashing damage. If the target is a creature, it must succeed on a Strength saving throw or be knocked prone. The DC of this saving throw is equal to 8 + your proficiency bonus + your Strength modifier.
Tusks. Your tusks are natural weapons, which you can use to make unarmed strikes. If you hit with them, you deal slashing damage equal to 1d6 + your Strength modifier, instead of the bludgeoning damage normal for an unarmed strike. If the target is a humanoid or fey, it must make a Constitution saving throw or be cursed with wereboar therianthropy. The DC of this saving throw is 8 + your proficiency bonus + your Constitution modifier.
Werelizard
Stats. Your Strength becomes 12, unless it is 12 or higher already, and your Constitution becomes 14 unless it is 14 or higher already.
Keen Taste. In all forms, you gain Expertise in Survival when making Wisdom (Survival) checks to track.
Shape Changer. Your beast-humanoid hybrid is a half-lizard. Your beast form is a Large lizard. While in either of these forms, you gain access to your Bite, Claws and Tail. In addition, while in your hybrid form or beast form, you gain a climbing speed of 30 feet.
Beast Scales. While in Beast or Hybrid form you gain +2 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons. This increase to AC does not stack with other natural armors.
Tail Whip. Your tail is a natural weapon, which you can use to make unarmed strikes. If you hit with them, you deal bludgeoning damage equal to 1d8 + your Strength modifier.
Claws. Your claws are natural weapons, which you can use to make unarmed strikes. If you hit with them, you deal slashing damage equal to 1d8 + your Strength modifier, instead of the bludgeoning damage normal for an unarmed strike.
Bite. You can use your action to make a special attack with your unarmed strike using your teeth. On a hit, the target takes piercing damage equal to 1d10 + your Strength modifier. If the target is a humanoid or fey, it must make a Constitution saving throw or be cursed with werelizard therianthropy. The DC of this saving throw is 8 + your proficiency bonus + your Constitution modifier.
Wererat
Stats. Your Dexterity becomes 13, unless it is 13 or higher already, and your Constitution becomes 10, unless it is 10 or higher already.
Skills. In all forms, you gain proficiency with Perception and Stealth.
Keen Smell. In all forms, you have advantage on Wisdom (Perception) checks that rely on smell.
Nimbleness. While in beast form, you have the ability to move through any Medium or larger creature.
Shapechanger. Your beast-humanoid hybrid is a half-rat. Your beast form is a tiny rat. While in either of these forms, you gain access to your bite.
Beast Hide. While in Beast or Hybrid form you gain +1 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons.
Bite. You can use your action to make a special attack with your unarmed strike using your teeth. On a hit, the target takes piercing damage equal to 1d4 + your Dexterity modifier. If you have the Sneak Attack feature, you can apply it to this attack. If the target is a humanoid or fey, it must make a Constitution saving throw or be cursed with wererat therianthropy. The DC of this saving throw is 8 + your proficiency bonus + your Constitution modifier.
Wereraven
Stats. Your Dexterity becomes 13, unless it is 13 or higher already, and your Constitution becomes 10, unless it is 10 or higher already.
Skills. In all forms, you gain proficiency with Perception and Stealth.
Keen Sight. In all forms, you have advantage on Wisdom (Perception) checks that rely on sight.
Nimbleness. While in beast form, you have the ability to move through any Medium or larger creature.
Shapechanger. Your beast-humanoid hybrid is a half-raven. Your beast form is a small raven. While in either of these forms, you gain access to your bite.
Beast Hide. While in Beast or Hybrid form you gain +1 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons.
Bite. You can use your action to make a special attack with your unarmed strike using your teeth. On a hit, the target takes piercing damage equal to 1d4 + your Dexterity modifier. If you have the Sneak Attack feature, you can apply it to this attack. If the target is a humanoid or fey, it must make a Constitution saving throw or be cursed with wereraven therianthropy. The DC of this saving throw is 8 + your proficiency bonus + your Constitution modifier.
Wereshark
Stats. Upon being cursed you get to choose your Strength becoming 14, unless it is 14 or higher already or your Dexterity becoming a 14, unless it is 14 or higher already. Once you make this choice it cannot be changed. Your Constitution becomes 12, unless it is 12 or higher already.
Ampullae of Lorenzini. In all forms, you have expertise in Perception when trying to perceive movement underwater.
Keen Sight. In all forms, you have advantage on Wisdom (Perception) checks that rely on sight.
Shapechanger. Your beast-humanoid hybrid is a half-shark. Your beast form is a Large shark. While in either of these forms, you gain access to your Bite. In addition, while in your hybrid form or beast form, your swimming speed increases by 15 feet.
Amphibious. While in hybrid form you can breathe air and water.
Gills. While transformed into your beast form you can only breathe underwater. If you are out of water while in beast form you begin to suffocate and can only hold your breath for 1 + your Constitution modifier minutes.
Fish Out of Water. While in beast form and out of water your walking speed becomes 5ft.
Blood Frenzy. While underwater, in beast or hybrid form, you smell blood in the water. As a bonus action choose one creature who has less than half of their maximum hit points within 10ft of you. You gain advantage on attack rolls against the creature for 1 minute or until it drops to 0 hit points or falls unconscious. Once you use this ability it cannot be used again until completing a long rest.
Beast Hide. While in Beast or Hybrid form, you gain +1 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons.
Bite. You can use your action to make a special attack with your unarmed strike using your teeth. On a hit, the target takes piercing damage equal to 1d10 + your Strength modifier. If the target is a humanoid or fey, it must make a Constitution saving throw or be cursed with wereshark therianthropy. The DC of this saving throw is 8 + your proficiency bonus + your Constitution modifier.
Weretiger
Stats. Upon being cursed you get to choose your Strength becoming a 14, unless it is 14 or higher already or your Dexterity becoming a 14, unless it is 14 or higher already. Once you make this choice it cannot be changed. Your Constitution becomes 12, unless it is 12 or higher already.
Skills. In all forms, you have Expertise in Perception checks that rely on sound, and Proficiency in Stealth checks to hide.
Keen Hearing. In all forms, you have advantage on Wisdom (Perception) checks that rely on hearing.
Lithe. While in beast or hybrid form, your jump distance is doubled.
Shapechanger. Your beast-humanoid hybrid is a half-tiger. Your beast form is a large tiger. While in either of these forms, you gain access to your Pounce, Bite, and Claws, and your walking speed increases by 10 feet.
Beast Hide. While in Beast or Hybrid form you gain +1 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons.
Pounce. In beast or hybrid form, if you move at least 15 feet toward a creature and then hit it with a claw attack on the same turn, that target must succeed on a Strength saving throw or be knocked prone. The DC of this saving throw is equal to 8 + your proficiency bonus + your Strength modifier. If the target is prone, you can make one bite attack against it as a bonus action.
Bite. You can use your action to make a special attack with your unarmed strike using your teeth. On a hit, the target takes piercing damage equal to 1d10 + your Strength modifier. If the target is a humanoid or fey, it must make a Constitution saving throw or be cursed with weretiger therianthropy. The DC of this saving throw is 8 + your proficiency bonus + your Constitution modifier.
Claws. Your claws are natural weapons, which you can use to make unarmed strikes. If you hit with them, you deal slashing damage equal to 1d8 + your Strength modifier, instead of the bludgeoning damage normal for an unarmed strike.
Werewolf
Stats. Upon being cursed you get to choose your Strength becoming a 12, unless it is 12 or higher already or your Dexterity becoming a 12, unless it is 12 or higher already. Once you make this choice it cannot be changed. Your Constitution becomes 12, unless it is 12 or higher already..
Skills. In all forms, you gain proficiency with Perception and Stealth.
Social Predator. While in beast or hybrid form, when you flank a creature, you gain an additional +2 to attack rolls against that creature.
Shapechanger. Your beast-humanoid hybrid is a half-wolf. Your beast form is a medium wolf. While in either of these forms, you gain access to your Bite and Claws, and your walking speed increases by 10 feet.
Beast Hide. While in Beast or Hybrid form you gain +1 AC and resistance to bludgeoning, piercing, and slashing damage from non magical attacks not made with silver weapons.
Bite. You can use your action to make a special attack with your unarmed strike using your teeth. On a hit, the target takes piercing damage equal to 1d8 + your Strength modifier. If the target is a humanoid or fey, it must make a Constitution saving throw or be cursed with werewolf therianthropy. The DC of this saving throw is 8 + your proficiency bonus + your Constitution modifier.
Claws. Your claws are natural weapons, which you can use to make unarmed strikes. If you hit with them, you deal slashing damage equal to 2d4 + your Strength modifier, instead of the bludgeoning damage normal for an unarmed strike.
Thank you Akbar for letting us use your therianthropes!