Drake Verdad is a angel-demon hybrid born from a union between his mom and dad who fell in love during the war. This union was however forbidden by both sides resulting in the family living in isolation until they boys found out of their powers at the age of 10. This forces their parents to fight against their brethren while almost dying. However the Demon King Muerte and Archangel Michael made a deal with them for their children's safety to never be hunted by both sides and that was to fight and kill each other in front of their children. Moriaty and Drake watched in horror as their parents tear each other limb for limb and eventually eradicated their souls in front of the boys. Drake and Moriaty swore they will kill them both in the most brutal fashion possible.
Drake as a boy who cared for his family a lot. Moriaty noted that he would refuse to kill anything and simply try to cure everything that hasn't died (like a person on terminal caner or an animal that lost its limbs). Drake was also noted to be while a fighter a pacifist as a child. But he changed to a ruthless killer who can even kill children as he is now driven by revenge. This resulted him being isolated and labeled as a monster even among the mercenary world.
At the age of 23 he massacred 100,000 churches around the galaxy and cult worshippers all over the globe and along with his brother accumulated a bounty worth of 6 sextillion zenny each because they have killed over several quadrillion people with brutal dismemberment and torture while stealing their souls. Drake intends to eventually kill the two people responsible for his parents death and make them suffer in the most brutal ways and kill anyone who gets in his way. However Drake is a civil enough person out of fighting and only kills people if provoked or if others have information needed to kill his true foes.