Heimdall

Heimdall (Old Norse: Heimdallr) is the watchman of the gods and guardian of Bifrost, the rainbow bridge connecting Asgard to the other worlds. He possesses extraordinary senses: he can see as well by night as by day, can hear the grass growing and wool growing on sheep. He never sleeps and requires very little food. Heimdall owns the Gjallarhorn, which he will sound at Ragnarök to summon all gods to battle. He dwells at Himinbjörg beside the bridge. According to Rígsþula, Heimdall walked among humans disguised as Rig and became the progenitor of the three human classes: thralls (þræll), farmers (karl), and earls (jarl). He is Loki's arch-enemy — the two slay each other at Ragnarök.