Who is MORE guilty of the deaths in Frankenstein? Please gauge the culpability of Victor and The Creature.

While both characters are guilty of crimes and wrongdoings in the novel, ultimately it must be Victor Frankenstein who bears the most blame. Victor is responsible for making the creature, for abandoning him, and for destroying the female creature, all of which leads to the deaths of the people closest to Victor. 

Before explaining Victor's culpability in more detail, we should recognize that the creature is a conscious, intelligent being who is aware of right and wrong. Though he is not "born" evil, and his crimes may even be somewhat understandable, the creature chooses to kill innocents in order to get revenge on or send warnings to Victor. The creature knows what he is doing when he kills William, Henry, and Elizabeth, and he commits these acts intentionally to hurt Victor. In other words, the creature is not blameless.

Victor, however, is most to blame because of the decisions he makes throughout the novel. His first mistake, of course, is building this creature and bringing it to life. He does nothing to map out how he will handle the creature once it is alive; his blind ambition leads him to act irresponsibly, and his lack of foresight ends in disaster. When Victor abandons his creature, he essentially refuses to parent it, and his absentee parenting contributes to the creature's anger and, later, to his vendetta against Victor.

Specifically in relation to the creature's murder of Elizabeth, Victor's wife, Victor had a chance to prevent the creature's violence. The creature tells him that he must build a female companion for the creature or he (the creature) will be with Victor on his wedding night. Most readers pick up on the threat here, but Victor, as usual, only thinks about how he personally will be affected and does not imagine that the creature would attack his wife. It is also worth noting that Victor knows that the creature killed William, but Victor allows Justine to be executed for the murder in order to save himself the public shame of admitting to what he has done in making this creature. If Victor had addressed the creature's violence responsibly, other lives could've been saved. 

Ultimately, Victor's actions are the root of all of the sins committed by the creature. While both characters share in the blame, Victor should be seen as more culpable for the way his decisions contribute to the creature's demeanor and motivations.