Helm

Helm, also called by the epithets the Watcher, He of the Unsleeping Eyes, and The Vigilant One, is the god of protection and vigilance. He's typically worshipped by guards, soldiers, and any who wish for protection.
The Helmhald Watchpoint in Eyjafjördur bears his name. He's a prominent deity in the Northern Pantheon. 
Helm is said to use a war horn that he blew back during the Dawn War.