Kain may refer to:
- The minor non-playable character from Final Fantasy II. He is a little boy that Ricard Highwind looks after.
- The character from Final Fantasy IV series.
- The dark doppelganger of Kain, who is mistaken for the real one, from Final Fantasy IV: The After Years.
Cain was the brother of Abel in the Tanakh/Old Testament book of Genesis. Cain became the first murderer by killing his brother out of jealousy stemming from God choosing Abel's gift over that of Cain.