Fiend

The Fiend starts with 3 Black Hearts. The Fiend can only have Black Hearts, and all hearts (whether they are dropped or gained through passive items, active items, or eternal hearts) will be Black Hearts(This effect is similar to Blood Tithe). He also drops all of his Black Hearts upon taking damage, although you can't pick them up until the room is cleared and they seek out enemies and attack them, dealing your damage. For example, if you have 5 Black Hearts, you will be left at half a Black Heart, and 4 Black Hearts will drop, although, if you are at 2 and a half, you will be left at 1 Black Heart, and you will also spawn one. This goes for 4 and a half spawning 3, etc. If you are at 1 Black Heart, no Black Hearts will drop. This means Champions and Spikes are very dangerous, and you can NEVER take damage on The Womb and further, as this will result in immediate death. This is not the case if you have The Wafer, or if you have a half heart. If you have 3 and a half Black Hearts on The Womb or farther and you take damage (Without The Wafer effect) you will be left at half of a Black Heart, and you will spawn 2 Black Hearts. He also starts with Homing tears, 4.0 Damage, 2.5 Shot Speed, 1.2 Speed, 10 Fire Rate, -1 Luck, and Normal Range

There, that should be most of it. Now someone just needs to format it better, I got the deetz, but not the skillz to format this shite.

Trivia

 * Fiend is based off of the :smiling_imp: emoji.