He might also find some allies. Leo can look for friends or even adults who can support him. If he has a good friend, they can walk together and the bully might be less likely to target him. And if he tells an adult like a teacher or a parent, they can take steps to stop the bullying.
Perhaps Leo is bullied in his neighborhood. There could be some older kids who target him when he's walking home from school or playing outside. They might take his things or push him around. This can make Leo feel scared and unsafe in his own neighborhood.
His friends are the most likely ones. They know his habits and routines well enough to pull off some great pranks. For example, if Leo is always punctual, they could set his alarm clock wrong to make him late.
Raph usually gets really angry. He blames himself for not being there to protect Leo or he gets mad at the enemy who hurt Leo. He'll be the first to want revenge and will be very protective of Leo while he's injured.
Well, in this fanfiction, Leo could be pranked by having his clothes swapped while he's in the shower. So he comes out thinking he's going to put on his normal outfit but instead gets something completely outlandish. Another possibility is that his friends set up a fake lottery win and then tell him it was all a joke.
Maybe it's a new villain in the fanfiction. Some powerful and evil character who sees Leo as a threat to their plans. This villain could use their unique powers or weapons to harm Leo. For example, a villain with the ability to control electricity could zap Leo and cause internal injuries.
It could be some of the lesser - known badniks that team up to bully Sonic. Since they can't defeat him on their own, they figure that by ganging up on him and bullying him, they can at least make his life difficult.
Well, it's popular because it taps into real - life issues like bullying. Many readers can relate to Deku's experiences on some level. Also, it creates a sense of drama and tension. We as readers are rooting for Deku to come out on top, and the whole process of seeing him deal with the bullies and grow stronger is very engaging. Moreover, it gives fanfiction writers a chance to put their own spin on the character and his backstory, which is always exciting for the fandom.