Some members of the pack might be angry at first. They could see his leaving as a betrayal, especially if they are in the middle of a difficult situation and rely on him in some way.
There could also be a sense of confusion. The pack might not fully understand why he's leaving and start to question their own actions and relationships. They may even try to figure out if there's something they could have done differently to make him stay.
Stiles might initially be shocked. He has been a part of the pack for a long time, and Scott kicking him out would be completely unexpected. He could stand there in disbelief, unable to process what has just happened.
Stiles might be initially shocked. He would probably feel betrayed since he thought of the pack as his family. He could go into a state of denial at first, not believing that they would actually kick him out.
Scott would be extremely worried and immediately start planning a rescue mission. He'd be angry at Theo for targeting Stiles and would use his alpha powers to try and track him down. He might also call on the rest of the pack for help, like Lydia, who could use her banshee powers to sense if Stiles was in danger or where he might be.
She could be angry at first. Tsunade has always been a strong - willed leader, and Naruto leaving without proper communication might seem like a sign of disrespect to her.
It could mean that in the context of a particular fandom, a group (the pack) doesn't pay attention to or show interest in fanfiction related to the character Stiles. Maybe they have other focuses within the fandom world, like other characters or storylines.
He might be really hurt. Stiles is a sensitive guy deep down, and having his friends, who are like family to him, forget his birthday would sting. He could go into a bit of a sulk and isolate himself for a while.
It can develop in many ways. Sometimes, it starts off rocky. Stiles' family may not understand the pack's ways. But as they get to know each other, they might start to respect the pack's loyalty to Stiles. For example, if the pack saves Stiles from a dangerous situation in front of his family, that could be a turning point.
Some might be shocked and feel betrayed. Harry is a hero to many, so his departure could leave them feeling abandoned. Others might understand his need for a break and respect his decision.
Chi - Chi might also be heartbroken. She loves Goku deeply despite his flaws. In fanfiction, she may initially be in denial, thinking that Goku will come back soon. But as time passes, she realizes that he may not return, and this could lead to a deep sense of sadness and loneliness. She has to then figure out how to raise their children on her own.
On the other hand, Stiles is also known for his quick thinking. He might start to try and bargain with Peter. He could offer to help Peter in some way if Peter lets him go. For example, if there's a problem in the supernatural community that Peter is facing, Stiles could say he'll use his human ingenuity to solve it. Also, Stiles could be angry. He might start shouting at Peter, calling him out on his actions, and trying to make Peter see how wrong this is.