Tyr

Tyr

This one-handed war deity is reputed to be the bravest of the gods. A sky god like Thor (they are brothers), Tyr is also a symbol of inflexible justice, and an implacable enforcer of the law. 
Tyr follows the Norse codes of conduct, which allow things like duels to the death and human sacrifice, so his idea of justice is very different from modem morality. One thing that he values is honor, and he will always keep his word. 
His bravery and honorable beliefs cost the god his hand. The Fenrir Wolf had become a danger to Asgard. The wolf allowed the gods to try to bind it, but always broke free. Finally, the dwarves manufactured a magical ribbon of mystical materials that would be unbreakable. Fenrir became suspicious and said that it would only let itself be bound if a god put his hand in its mouth as security that it would later be released. 
If this was a trick, Fenrir would bite off the god's hand. Tyr, who hated the lies Odin was telling, was the only god who came forward and offered his hand. Fenrir was bound and could not break free. Enraged, it bit off Tyr's hand as Tyr knew it would. 
Tyr is always guarding Asgard against any external threats. He keeps a close watch on the Norse giants and their allies, and sometimes travels to other worlds to investigate rumors that might be valuable or important to the security of the realm.

God of Justice