Note : The strategies for each phase assume you don’t have the Fierce Deity’s Mask. If you do, don the mask and lock on to Majora’s Mask and simply swing repeatedly. The damage you deal with the attacks is incredible and warrants no strategy to defeat the boss.
The Mask is invulnerable to frontal attacks so you need to hit it in the back. You can hit it in the back with Arrows but that’s a bit difficult.
The easiest way to counter is wait for the mask to spin at you then simply execute a Quick Spin Attack to inflict damage and stun it. Use the Great Fairy’s Sword to inflict the most damage while it’s down.
Midway through this exchange the Boss Remains will come off the walls and begin shooting energy beams at you.
At this point you’ll want to reflect Majora’s Mask’s fiery attack into the Boss Remains to defeat them in a single hit, then continue to damage Majora’s Mask.
Majora’s Mask will move to the center of the room and sprout arms and legs!
This fight is simple if you know the mechanics. This creature moves around the room very fast, but if you hold up the Mirror Shield you can walk towards it and then shoot it with an arrow to stun.
At this point simply attack with the Great Fairy Sword and repeat. You’ll get blown away and knocked back often, but if you keep the Mirror Shield up and locked onto the boss you’ll avoid damage.
The boss morphs once more and now has long deadly tentacles. Guard against them and quickly fire Light Arrows into him to stun him.Sometimes he’ll be at a distance and taunt, hit him with Light Arrows at this point too.
Use the pots around the room to get more arrows if you begin to run out and use the Great Fairy’s Sword to inflict the most damage while Majora’s Wrath is stunned. In short, keep your distance and guard until you can launch a Light Arrow.
Midway you’ll encounter spinning tops that deal damage and can explode, so stick to the walls so you can always see them. Hug the wall and progress towards Majora’s Wrath with your shield up then loose a Light Arrow when you’re close enough.
Head in for the killing the blow to trigger the final cutscene and the credits.