Well, typically in 'oc that just dont care fanfic', the original character might have a laid - back or nonchalant attitude towards the events in the story. They could be indifferent to the typical drama or conflicts that other characters are facing.
I'm not sure specifically which 'oc that just dont care fanfic' there are. You could try searching on fanfiction platforms like Archive of Our Own or FanFiction.net using relevant keywords to find such works.
Well, it could be in a situation like a conversation where northernlion started talking about his past, his dreams, his daily routines and so on without the other person being interested in such a deep dive into his life. The other person then snapped and said 'i didnt ask for your life story' to make it clear that northernlion was oversharing and they just wanted a more focused or brief conversation.
Maybe northernlion is a co - worker. In a work - related conversation, he might have started to share a lot of personal details that were not relevant to the work at hand, and that's why the statement was made. He could also be a person from an online community or a gamer, for example, if this statement was made in the context of an online chat or a gaming session.