Parentage:
He's sometimes said to be a son of Odinn, and other times said to be the son of the giant Hymir.
Consorts & Children:
His only known consort is Zisa, a female version of him.
Notable Stories Involving Him:
He's often portrayed as being one-handed, having lost his other hand to the monstrous wolf Fenrir. The other gods were trying to trick Fenrir into being chained up, but he demanded a sign of good faith in return, so Tyr bravely stepped forward and placed his hand in the wolf's mouth. When Fenrir discovered the trick, however, he bit off Tyr's hand. Due to this, Tyr is considered an honorable god, upholding oaths and the law. As the god of war, he can be invoked to ensure victory in battle, though he used to also be recognized as the king of the gods before being replaced by Odinn, with whom he shares the responsibilities of war god. When Ragnarok, the end of the world, arrives, he'll kill the hell-hound Garm, but also be killed by him in the process. He's sometimes also called Tiwaz or Tiw, and it's from the latter that we get Tuesday (Tiw's Day).
Sacred Symbols:
His only attribute is a spear, a symbol of justice to the Norse peoples.
Tyr Around the World:
The Romans identified him with their Mars.
SOURCES: Wikipedia, Encyclopedia Mythica, & The Ultimate Online Resource for Norse Mythology and Religion