Odolwa is the boss of Woodfall Temple. As a Deku Scrub, use the Deku Flowers in the arena to launch yourself into the air and drop Deku Nuts on his head to stun him. While he's stunned, switch to human Link and attack him with your sword. Be wary of his sword attacks, fire breath, and summoned insects. Repeat this strategy until he is defeated. Upon victory, you'll receive a Heart Container and Odolwa's Remains.
