In Deadliest Warrior: Legends for the Xbox 360, you can enable the god mode cheat code to make your character invincible. Note that turning on these cheats will disable achievements until you restart the game.
At the main menu, press the following codes for the desired cheat.
God Mode for Player 1 – Up, A, X, B, Y, Down
God Mode for Player 2 – Down, B, X, A, Y, Up