For the antisocial part of his backstory, when he finds someone that he begins to trust as, at the very least, an ally, he starts to cling to them out of the fear of being left to himself again. However, being an outsider, he's a walking trouble magnet, and this causes the people he's clinging to to see him as a pain in the ass and push him away.
And for the life lesson... well, Marisa shows up to steal his stuff, but he gets the upper hand and takes away her Hakkero. He acts without thinking and tries to use it, and ends up blasting himself all the way into Yuuka's territory, drawing Yukari to his position (in my story, Yuuka hates Yukari because of how much she trolls people). This bites him in the ass when Yuuka decides to track him down and nearly kills him, while causing a lot of grief for other characters at the same time.
And for the life lesson... well, Marisa shows up to steal his stuff, but he gets the upper hand and takes away her Hakkero. He acts without thinking and tries to use it, and ends up blasting himself all the way into Yuuka's territory, drawing Yukari to his position (in my story, Yuuka hates Yukari because of how much she trolls people). This bites him in the ass when Yuuka decides to track him down and nearly kills him, while causing a lot of grief for other characters at the same time.
Sounds really good! I like it!
But now the next step is this: Show, Don't Tell.
But now the next step is this: Show, Don't Tell.