- – Matt Mercer, probably.
The Blood Hunter is a homebrew class created by Matthew Mercer of Critical Role and voice-acting fame for 5e, released as a semi-official class on DnD Beyond through a marketing deal. The class is something between the Fighter Monster Hunter subclass, a really gross Paladin and a bit of the Rogue's "preparing before a fight" sentiment, which creates a martial, but kind of frail warrior who are at their best when they can duel one enemy and prepare for countering its strengths. With access to Light and Medium Armor alongside shields and a D10 hitdie they're about as tough as Fighters starting out, but they need to be due to the class' main draw, Hemocraft. It draws power from your HP - at least if you want to make a ding dang difference in combat and not just be a hamstrung Fighter with anemia. It allows the Blood Hunter to weaken the enemy with curses, empower their weapons and all sorts of other nifty things, all through the power of cutting their wrists - but don't do this yourself kids, it won't make you able to blood-curse that bully Richard who pissed on your Player's Handbook. It may make him sad, though.
Speaking of which, Blood Hunters easily competes with the Rogue for the most edgy, dark-but-misunderstood class in the game. Blood Hunters are members of hidden Orders who study and experiment with blood, empowering themselves to become as powerful as the monsters they face. But they must look out for themselves and guard their secrets well, lest they become like the monsters they hunt... It is a razor's edge they walk, where the common folk despise you while you despair at the horror you do upon yourself for the greater good- You asleep yet? Good, just checking.
Of course, nothing's stopping you from just playing however you want to. Just make sure your Blood Hunter has a great, black leather coat, a flaming sword and a dark, inscrutable past with a Chaotic Good/Chaotic Neutral Alignment and you're set to go.