Humanoidshape. You can use an action and bonus action to adopt a humanoid form and regain use of your base class features.

Dracocurse. Certain class features risk Straining yourself, thereby exacerbating your curse. If this happens, gain 1 level of Strain and take 1d4 Necrotic damage for each level. Lose 1 level of Strain when an ally Helps you. Lose all Strain through the effects of Lesser/Greater restoration, or a short rest. It is no longer difficult to regain your humanoid form when your curse is exacerbated.

Dark Reprieve. Due to your exposure to the Gentle Darkness, you gain resistance to all necrotic damage, including that taken by strain. 

Profane Smite. Once per turn, when you make a single successful melee attack, you can expend a spell slot to add 2d8 necrotic damage. The damage increases by 1d8 by every spell slot used above level 1, to a maximum of 5d8 damage.

Flawed Multiattack. Requires <4 Strain. Once per short rest, make three attacks (one each with claw and bite). After doing so, Strain yourself. If you miss any of the attacks, Strain yourself again.

Bite. +5 to hit, 10ft reach. 2d10 + STR piercing damage.

Claw. +5 to hit, 5ft reach. 2d6 + STR slashing damage.

Cursed Cold Breath. Requires <4 Strain. 30ft cone. Deals 3d8 Necrotic and 3d8 Cold damage. DC 17 DEX saving throw to halve that damage. Strain yourself.

Shared Lash. When you are hit with a melee attack, you can use a reaction and Strain yourself to deal 3d10 Necrotic damage to the attacker.