Which Norse god is the watchman of the gods and guards Bifröst?

Heimdall is the Norse god who watches over the gods and guards the Bifröst bridge. He lives at Himinbjörg, the heavenly dwelling near the bridge, where he keeps watch for hostile jötnar and other threats approaching Asgard.

Mythic descriptions give Heimdall extraordinary senses. He needs less sleep than a bird, can see exceptionally far—even at night—and can hear remarkably faint sounds. His golden-maned horse is Gulltoppr, and his most famous possession is Gjallarhorn, a horn whose blast can be heard throughout the worlds.

Heimdall’s guardianship becomes especially important at Ragnarök. He sounds Gjallarhorn to alert the gods that the final conflict has begun, then fights Loki. The two enemies kill one another in the battle. Heimdall is sometimes confused with Marvel’s version of the character, but the mythological figure is presented as a boundary keeper and herald of catastrophe, not simply as a warrior stationed on a rainbow bridge. Odin, Thor, and Loki are separate figures with different roles.