In order to beat Ganon, you will NEED to use all your WEAPONS. That is using your Bombs, Arrows, Boomerang and Hookshot. The trick to beating Ganon is studying his attack patterns and using the right item at the right time. By this I mean, memorizing which animation initiates the different attack and then use the right item to counter-attack.
Ganon has four attacks and here’s how to counter-attack.
Fireball – Ganon’s right hand will charge a large fall ball which has great range. Throw a bomb while the fireball is charge to cause his gauntlet to be damaged.
Electric ball – Ganon’s Right hand will charge a large electric ball which fires with decent speed.
Unlike the fireball, you will need to wait after Ganon shoots the ball, doing so you should notice an eyeball on his gauntlet; shoot the eye with an arrow. Raised Fire breather – This one should be a little easy to recognize. Ganon will fly up in the air and begin to breath out fire, at the end of the attack you should see his tail glow brightly, use the hookshot to rip-off the tip of the tail.
Bullet Spray – Ganon’s last attack will fire dozens of pellets from the large horn-like-thing on his shoulder at the floor, use your boomerang to smack the first horn. You will need to do this again to destroy the second horn.
Having reach this point a cutscene will activate, which will should give you access to the light arrows. Again, there is a small window of opportunity where the Light Arrows are effective. You’ll notice when after Ganon’s ram-charge attack, his forehead glows purple, this is the opportunity to use the arrows. Correctly timing the shoot will stun Ganon, giving you free reign at his body. Rinse and repeat until Ganon has been defeated once and for all. Congratulation for beating Hyrule Warriors. I hope this guide was helpful.