what is heimdall the god of

Heimdall is a god in Norse mythology, known as the watchman of the gods and the guardian of the Bifrost, the rainbow bridge that connects Asgard to the other worlds. He was the son of Odin and nine mothers. Heimdall was known for his keen eyesight and hearing, and he could see and hear all that happened in the Nine Worlds. He was also believed to be the one to introduce a class system to human beings. Heimdall kept the "ringing" horn, Gjallarhorn, which could be heard throughout heaven, earth, and the lower world. It was believed that he would sound the horn to summon the gods when their enemies, the giants, drew near at the Ragnarök, the end of the world of gods and men. Heimdall was also known as Gullintani ("gold tooth") and his horse was called Gulltopp, "the horse with the golden mane".