Brutus from 'Julius Caesar' is a very notorious betrayer. He was so close to Caesar, seen as a friend, yet he took part in the assassination plot. His actions were driven by his belief that Caesar was becoming too powerful, but his betrayal was still a huge shock. Then there's Iago from 'Othello'. Iago manipulates Othello into believing his wife Desdemona is unfaithful, all out of his own jealousy and spite, which ultimately leads to tragic consequences.
One of the top betrayals in fiction is Judas Iscariot's betrayal of Jesus in religious literature. His kiss in the Garden of Gethsemane led to Jesus' arrest. Another is Brutus' betrayal of Caesar in Shakespeare's 'Julius Caesar'. Brutus, a trusted friend, joined the conspiracy against Caesar, stabbing him. And in 'The Lord of the Rings', Saruman's betrayal of Gandalf. Saruman, once an ally, turned to the dark side, trying to get the One Ring for himself.
This question was not easy to answer because the quality and evaluation of the male lead in the anime depended on many factors such as the plot, character creation, audience preferences, and so on. Moreover, the definition of "the most scum" varied from person to person.
However, if it was referring to the performance of the male lead in a certain anime, then it could be said that every character had its own unique charm and value. It was difficult to simply rate a character as the "worst".
One of the best betrayals in fiction is in 'Macbeth'. Lady Macbeth betrays her own moral code and manipulates Macbeth into murdering King Duncan. This act sets off a chain of tragic events that ultimately leads to their downfall.
In my opinion, 'High School DxD' had some issues as an anime adaptation of a light novel. While it was popular for its fanservice, it deviated quite a bit from the original light novel in terms of story and character growth in the later seasons. The story started to feel more like an excuse to show off the female characters' bodies rather than focusing on the plot and character development that was in the light novel.
In 'The Godfather', Carlo Rizzi betrays Sonny Corleone. Carlo, who was married to Sonny's sister Connie, sets Sonny up to be killed in a trap. He does this out of jealousy and resentment towards the Corleone family. Also, in 'Macbeth' by Shakespeare, Lady Macbeth betrays her own moral code. She encourages Macbeth to murder King Duncan so that he can become king, which leads to a downward spiral of guilt and more bloodshed. Then there's the betrayal of Edmond Dantès in 'The Count of Monte Cristo' by Fernand Mondego. Fernand, who was once Dantès' friend, helps send him to prison out of envy and to win Dantès' fiancée.
I'm not sure specifically as I haven't read it. But generally, it might be about various bargains people make and the subsequent betrayals that occur within the context of the story in the '13 to life' world.
Judas Iscariot from the Bible stories (which are also a form of religious fiction in a sense) is very well - known for his betrayal. He betrays Jesus for thirty pieces of silver, which leads to Jesus' crucifixion.
I'm not sure specifically which are the top 10 worst as it can be very subjective. However, some stories might be considered bad if they have extremely poor grammar, a very unoriginal plot like the typical 'love triangle' done in a very clichéd way, or characters that are completely one - dimensional.