V is the masked protagonist with a pronounced knack for theatrics. A man with a mission yet to be unveiled.
V is a survivor of the Larkhill. He was injected with the Batch 5 by Delia Surridge which endowed him with some superhuman abilities.
V puts freedom over law and justice. In his monologue in Volume 02, before destroying the sculpture of justice, he eloquently expounded his view on this matter.
Acts of vendetta V executed are not always lethal. However, it doesn't seem to be consistent either. We can see that he has been killing people from Larkhill long before the detectives noticed. However, we can assume that these villains are minor compared to the ones we see in the novel. It doesn't make sense why they all got killed but Prothero wasn't.
V abducted Lewis Prothero from a train and put him in a re-enactment setting of Larkhill in Prothero's time with an overdose of Batch 5 injected followed by burning of all of his dolls.
This act does full justice to the word vendetta. The re-enactment ensures that the villain is well aware of his crime. The burning of dolls is a particularly potent punishment due to Prothero's obsession with dolls, and the burning itself is a reminder of concentration camps.
Bishop Anthony Liliman
V lured Lilliman using Evey, and killed him using a poisoned wafer.
The Vendetta against Delia Surridge shows some sense of empathy on V's part. V injected him with poison while she was asleep and was very kind to her through the last minutes of her life.