I have chosen Sheesh's Miasma and lordvahk97's Martyr as the winners of the recent character competition. The Martyr also resembles Watermelon's Gladiator character.
The Miasma has been renamed to Doctor. He has a memento unique to him that causes all healing to build up the poison meter instead, and health is slowly restored when actually afflicted with poison. He can also convert blood slimes into allied acidic oozes.
The Martyr has generally poor stats, but excels when at low health. He carries everyone's favorite memento (Rat Tail) as well as two new mementos that significantly slow the time to bleed out and greatly increase damage, dexterity, and speed while bleeding.
These characters will be included in Update 0.9.10 which is set to release this week (probably Friday).
I went through each suggestion multiple times, weighed the pros and cons, and tweaked possibilities. Thank you so much Watermelon, Sheesh, Gun_Shy, lordvahk97, redlid, stupidyou3, King, Nebu, TuneCat, RainyLime, and Sir Pib for participating :)