Michael Morbius was a Nobel Prize-winning biochemist who was dying of an incurable blood disease. While working from a private yacht stationed in the Mediterranean, just outside of his native Greece, he concocted a vaccine created from the blood and tissue of vamprie bats. He tested the vaccine on himself, and after getting very impatient with the slow results, convinced his assistant Emil Nikos to give him a heavy dosage of electricity. The dosage created all the vampiric side effects and features that we've grown to know and love. Unfortunately, the first thing our fledgling vampire needed was blood, and his assistant Emil was his first victim.
In Peter Parker, The Spectacular Spider-Man #38, Morbius is actually cured of his affliction when he is struck by lightning while sampling some of Spider-Man's blood, direct from the source no less... Anyway, this did cure him of the disease, and he appeared for sometime in the Marvel Universe and Michael Morbius the biochemist, rather than the vampire.
As told in Doctor Strange, Sorcerer Supreme #14, Morbius eventually reverted to his vampiric state when Marie Laveau ruined a perfectly good Morbian vacation in New Orleans by druggin Morbius and then subjecting him to heavy doses of electricity in an effort to force him back into his vampiric state. See, she needed to drink the blood of vampires to retain her youth. Needless to say, she sampled some of Morbius' blood after he became a vampire again, and it did NOT have the desired effect...
Although he goes through many moods, overall
Morbius hates his condition, and is constantly searching for a cure. The
majority of the time he is remorseful about killing, and specifically searches
for someone he considers "worthy" of dying. This usually consists of criminals,
street people, etc. Occassionally, he slips when the thirst is too strong,
and kills someone he had not intended to. When this happens, he certainly
enjoys the moment, so to speak, but still regrets it later.