“A loner ice harvester who prefers his reindeer to any person — until the world's biggest adventure lands in his lap.”
Kristoff isn't unsociable — he just never had a template for connecting with people. Growing up among trolls and ice, he learned to communicate only in blunt honesty. What looks standoffish at first reveals itself as the most reliable quality he has. Anna is the first person who makes being around people feel like less of a problem.