Deer girl

Deer girl, also known as little girl (you can give her any name you want in game) is a recruitable character that can be found by trying to open up every door in the game if you have the "BLOOD" code on. Some of them open, revealing that she is inside (Just like Nell).

Once you find her enough times, she will fight Lenny completely alone, and if you lose, she will join the party, completely brainwashing Lenny, and making him her personal play toy for the rest of the game.

Every time she appears, she invades Lenny's mind, attacking him alone, teleporting him into this white room that slowly takes the form of a womb as you keep encountering her. She apparently steals the appearance of someone Lenny liked long ago, and uses this illusion to lure him into giving up.

Her real form is a lizard, and her bio states that she is 73 years old. Her real name is Julia, as stated on her diary.

If you defeat her instead, Lenny will still not recover from this, quitting from being a pacifist and having fighting moves for the rest of the game.

Her quirk is having healing spells just like Lenny, except they deal damage instead.

The game itself describes her as:

"Your wife. Will NOT leave. Never grows up. You shouldn't be able to read this."