The term 'Son of Odin' refers to four figures in Norse mythology: Thor, Baldur, Tyr, and Vali. Thor is the god of thunder and the strongest of the gods. Baldur is the god of light and beauty, and is known for his innocence and purity. Tyr is the god of war and justice, and is known for his courage and strength. Vali is the god of revenge and is known for his swiftness and cunning. All four are sons of Odin, the chief god in Norse mythology.