pedophile - one who is into pre-pubescent children
_____phile - one who is into incest?
Is there a single word that fits into "He's a ______" to describe someone who is into incest?
A hyphenated word is fine.
Incestuous (adj): (the noun is incestuousnesses)
- adj. Of, involving, or suggestive of incest.
- having committed incest.
A less common term is incestophile according to Wikipedia:
- A person who engages in incest is called an incestophile.