Your appearance has grotesquely transformed. Your skin becomes red and leathery, and vicious horns, teeth and nails erupt through the surface
of your skin. You can suppress this form and present the appearance of the humanoid you once were, but this is taxing and requires concentration. Moments of stress are likely
to reveal your true nature. In the following situations your true form is revealed:

• Concentrating on a spell.
• Gaining the unconscious condition.
• Entering hallowed ground.
• Choosing to reveal yourself.

In events of extreme emotional or physical stress, a GM may call for a Constitution saving throw with a DC of their choosing to see if you maintain
your humanoid form. Non-evil creatures that witness your true form become instantly hostile to you, unless the GM decides otherwise.