This one, I think... :)

This is an example of a huge, unexplained backstory in Frozen. He was following around the ice guys... was one of them his dad? He refers to the trolls as his friends, not his family, so my guess is that one of the ice guys was his dad but he frequently visited the trolls. When he visits them he exclaims how big they've gotten, etc etc so I feel like he just visited them a lot. I'm really not sure about him. Kristoff is a highly unexplained character and this really bugs me. The only thing that throws me off about this explanation is when that woman troll says "Cuties... I'm gonna keep you" and Kristoff doesn't seem confused or frightened.

I know he said that he never really had a home until the trolls took him in, but how did they ice men not notice the kid was on dangerous ice or even allow him there if one of them wasn't his father? Was his father abusive and that's why he said he was always on his own? (which would also explain why he didn't like people) Was he just an orphan trying to make some money? WHAT THE HECK? People complain the The Swan Princess has a lot of plot holes and... well, it does, but I still love it. Either way, it makes The Swan Princesses plot holes look very minor! This movie has WAY too many plot holes that it's just lazy and poorly explained. Boy, when I rewatch this movie for my Frozen review article, I'm gonna have a lot to rage about. I have a feeling I'm going to go all Nostalgia Critic on it. I'm probably overreacting but this is one of the main plot holes that just IRKS me to no end.

I don't trust the trolls...

Or "he didn't live with them."

Wasn't it hinted at that the trolls took him in and he lived with them??

Maybe.I really don't get it he was working with men cutting ice and out of no were he starts to live with the trolls, even if he was an orphaned there should had been one out of those men that toke care of him, confusing.

I really wish they had explained this better! I just assumed the trolls took him in, and the ice men never came looking for him because they didn't take much notice of him/he was an orphan... but really, I have no idea.

My guess is that one of the ice guys was his dad and his mother was dead. It seems to me like the father had taken Kristoff with him to the job because Kristoff wanted to, and then at night Kristoff was going home alone because the father and other ice men were going to sell the ice somewhere farer and couldn't take little boy with them. In my opinion Kristoff was just playing all day there, in the end he got just one little piece of ice. Also if he had eg fallen in water or something like that his father and others would have helped him.
I think Kristoff's father died later while he was still a kid and he would have moved around being stable boy or something like that until he was old enough to do real job. And visiting trolls every now and then.
I can't believe he would have lived among the trolls, for a one because those lived just out there in a forest. He would have died during winter, and there was nothing he could have to eat. Also during Fixer Upper he didn't really have a clue what the trolls were up to, if he lived with them he probably would have learned to know them a little better.

Yeah well, it's just a guess.. But he couldn't have lived with them, I'm sure of that.

But how did the trolls know he was orphaned?

shady trolls