How to Obtain
The horn of Heimdall in Norse mythology. Heimdall was the god who guarded Bifrost, the rainbow bridge to Asgard, abode of the Æsir (New Norse gods). This horn was used as an instrument. It was hidden beneath Yggdrasil, the world tree and it was prophesized that it would be used to announce the beginning of Ragnarok, the end of the world in Norse mythology. Gjallarhorn means "ringing horn".