The Ink Demon

The Ink Demon is an antagonist of Lampblack City, and the monster form of Bendy. Striker believes The Ink Demon and Bendy are one in the same, which he is correct about.

Appearance
The Ink Demon looks nearly identical to his cartoon counterpart, but this form is incredibly tall, and his ink is melted over his eyes and deformed in a horrific way.

Personality
It can be reasonably inferred that Bendy changes into The Ink Demon against his own will, as stated here:

"Bendy and “The Ink Demon” are the same, Striker is just trying to make sense of what he’s of seen of all Bendy’s forms so far. Bendy is more than happy to change into a silly inanimate object in front of a crowd, but his scarier and less voluntary forms are mostly a secret to the public. The Butcher Gang isn’t really considered a part of that group, since JD studios toons are all pretty aware of what each other is and can do and has done, but Striker lives in another neighborhood and isn’t close with Bendy. He’s caught a glimpse of Bendy’s canon-y beanpole form, and of course he knows the little ‘friendly’ Bendy exists, they run into each other plenty, but he hasn’t actually seen him transform. Neither have Charlie or Barley, but they have probably put it together themselves. Striker’s not stupid, he just has different ways of prioritizing his thoughts."

He kills whoever he encounters, showing a mercilessness to him. He strikes fear into everyone that knows about him. Striker claims he is "a gimp, dumb and blind".

Trivia

 * He hates when the Bendy cutouts and pictures are removed.
 * He is one of Bendy's forms, this one likely against his will.