Sven

Sven is the loyal pet reindeer and companion of Kristoff, a rugged mountain man. Together, the duo run an ice harvesting business (which has greatly enhanced Sven's overall strength, making him quite the force) and reside outside the city of Arendelle in the Valley of the Living Rock, where a community of trolls thrive. The trolls adopted both Kristoff and Sven as children, and raised them. Also, according to Frozen: The Essential Guide, Sven was rescued by Kristoff as a young fawn, and remained by his side ever since. Though Sven cannot speak, Kristoff has come to fully understand the reindeer merely through the latter's actions and expressions, to the point where he does his own voice-overs for Sven.