There were many novels about betrayers of marriage, such as " Why the Silent Flute "," Flowers Are Not Flowers, Fog Are Not Fog "," Three Lives Three Lives Ten Miles Peach Blossom "," Chu Qiao's Biography ", and so on. These novels were all about the betrayal of marriage. The protagonist experienced all kinds of pain and struggle and finally found a way to redeem himself.
In a typical 'betrayer game story', there could be a lead character, let's call him Jack. He might be a very strategic player. There could also be his comrades, like Mike and Lisa. Jack could be the one tempted to betray Mike and Lisa for a big prize in the game. Or, there could be an antagonist character, say Eve, who is constantly looking for opportunities to make others betray each other for her own amusement in the game world.
I'm not sure specifically which 'betrayer game story' you mean. There could be many stories with this title or related concept. It might be about a game where there are betrayers among the players, perhaps in a survival or strategy game setting where trust is broken and alliances are shattered.
In some versions, it could be an evil version of one of Tails' friends. Maybe through some dark magic or experiment gone wrong, Sonic or another friend turns against Tails. Their altered state makes them see Tails as an enemy, and they start to undermine him and try to harm him, which would be a huge betrayal for Tails.
It could be Valerie. She has had a somewhat rocky relationship with Danny in the original series. In a fanfiction about betrayal, she might be pushed over the edge by jealousy or a misunderstanding about Danny's powers and his intentions. She could then use her ghost - hunting skills against Danny in a more malicious way than before.
A new character could be introduced as the betrayer. This character could be a fellow robot created by the same technology as Mega Man but with a corrupted program. This character could pretend to be on Mega Man's side, gain his trust, and then stab him in the back when he least expects it.
It could be Sakura. Maybe she becomes envious of Naruto's newfound godlike status. She might feel that he has changed too much and is no longer the Naruto she knew. So, she could side with those who want to bring Naruto down, either out of jealousy or a misguided sense of what's right for the village.
Another possibility is that it could be a new character introduced in the fanfiction. This new character could be someone who gains Harry's trust quickly but then betrays him for personal gain or because they are secretly working for an enemy. For example, a new student at Hogwarts who seems friendly at first but is actually a spy for a dark wizard.
A love interest is also a common choice. In fanfictions, love can be a complicated and often treacherous thing. The love interest could have their own motives, like being forced by an external power or having a hidden agenda that conflicts with Fem Robin's goals.
It could be Vegeta. Maybe in this fanfiction, his pride gets the better of him and he feels overshadowed by Goku and Gohan's power. So he fabricates some lies to make them look like traitors to the rest of the group.