I'm not sure specifically which 'iam tongi' you are referring to. There could be many people with this name or it might be something relatively unknown. More context would be helpful to tell the back story.
Well, first we need to know who 'iam tongi' is. Is it a person? A brand? Without knowing that basic fact, we can't really start on the back story. Maybe if it's a person, we need to know their nationality, their interests, and their upbringing to piece together the back story.
It adds a new dimension to the Sonic fandom. It gives fans a different way to explore the relationships between characters. For those who love Sonic and Blaze, it satisfies their desire to see them in a romantic context. It also encourages creativity among fans as they write and share these fanfictions.
Well, it could be about Sonic taking on a darker form or personality. Maybe there's some kind of evil influence that causes him to go dark, like a powerful dark artifact or an encounter with a really bad villain that messes with his mind and makes him turn against his friends.
There could be new original antagonists created specifically for the fanfiction. These might be dark entities that are related to the source of Dark Sonic's power, trying to either control him or use his power to spread chaos in Sonic's world.
Well, 'sonic x sonic to the rescue fanfiction' could potentially center around Sonic characters coming together to rescue a friend or a group in trouble. It could include exciting chase scenes with Sonic's incredible speed being put to good use. There might also be some unique power - ups or abilities that the Sonics discover during their rescue mission. It could also explore the relationship between the two Sonics, whether they have different personalities or if they work in perfect harmony right away.
One common element in the Sonic turns into Dark Sonic fanfiction could be the role of antagonists. They might have a hand in triggering this transformation. For example, by manipulating Sonic's emotions or by using some sort of dark magic. Once Sonic becomes Dark Sonic, his relationships with his friends like Tails and Knuckles also change. His friends may try to bring him back to his normal self, which can create a lot of drama and action in the fanfiction.
One possible theme could be self - discovery. Sonic discovers new aspects of himself during the events of Sonic Unleashed, and this could be a central theme in the fanfic.
His friends like Tails and Knuckles are likely to try and save Sonic. Tails is smart and could come up with a clever plan, while Knuckles has the strength to fight off Scourge if needed.