What the hell exactly is he?

Majora's Mask was sealed up for its power to destroy worlds. It was locked away for all eternity, never to be abused again... until the Happy Mask Salesman found it. He took it from its hiding with the reasoning that he should keep it safe. However, I wonder, why did he think that he could keep it safer than wherever its guardians had initially hid it? We know that the mask "grants" power to those that wear it, but does it have influence over anyone else? I believe that the mask has a kind of subconscious suggestion, similar to the One Ring, that it uses to arrange the world around it. It was sealed away without guardians to prevent its guardians from being subject to its power. So when the HMS found it, instead of following better sensibility and leaving it, he allowed the mask to give him one tiny idea - "take it with you. It's not safe here." And so he did. However, as he kept the mask with him, he didn't realize that it had been slowly increasing its influence on him. Slowly. And while he did this, he explored all of Hyrule, meeting many faces, such as Malon at Lon Lon Ranch, Darunia the goron, and more characters, all ones that Link, the Hero of Time, had met. And all the while, the Mask was observing his meetings, his memories, his knowledge of the people around him, slowly calculating a plan to bring devastation to this world.
Some time later, the Salesman got a novel idea - he should explore the Lost Woods for more masks! He entered the dangerous wood with bravery, and the Mask observed from his bag. The salesman had crossed several denizens' paths, but none of them were suited. Until he met Skull Kid, of course. The Mask spotted Skull Kid from the woods, just barely visible from the bag, and it gave him one idea. "What is that colourful thing in his bag? I want it!" And so Skull Kid mugged HMS, taking Majora's Mask for himself. Once he wore it, he relinquished his body to the Mask's full whims, allowing it to take control of him.

but he took over the body of a boy

The mask then makes Skull Kid go on a hunt for Link, to lure him into the Mask's trap, because Majora has formed a plan: Link has touched everyone in Hyrule in one way or another. It sensed that Link had some kind of great influential power, far greater than its own. It knew that it could not control someone with such fortitude, so it chose to break him first - destroy his mind and sanity to leave him as an empty husk of power, for Majora to steal away and use. When Skull Kid meets Link, he mugs him and steals his horse, running off into a tree hollow. It seems like a very odd area to run, since there is nowhere to hide, yes? But, once Link enters, he falls into a strange, impossible world, and wakes up as a Deku Scrub.
Notice, though. Skull Kid shows none of his trait supernatural powers while mugging Link. He has his fairies scare Link, and he rides his horse away, without any floating or telekinesis. Just simple trickery. But as soon as Link falls into the tree, Skull Kid is able to bend reality itself. Opening and closing doors, flying, and controlling Link. This is because Link hasn't fallen into another land, but has rather entered a fictional world created by Majora. Every person Link meets looks exactly like someone that he has met in the past. The song of time suddenly has actual power over time. These are just some of the clues that Termina isn't a physical place. They hint at a much darker fact: Termina was designed to make Link weak, playing against his greatest flaws.
Link is a courageous hero, touched by the triforce. He attempts to save everyone he meets. So of course, Termina would be Link's worst adventure yet - a world where he is faced with the end of the world repeatedly, in a very tight time constraint.

>What the hell exactly is he?

The only memorable Zelda antagonist besides Ganon

He has to choose who lives, who he saves. Should he spend all three of his days saving Anju and Kafei? Or what about Romani and Cremia? Or should he focus on the task at hand? Link is forced to watch people die around him repeatedly as he saves the world, with the intended effect of driving him insane with guilt and sorrow.
Majora underestimates his strength, though. Link is able to continue, slaving through the increasingly difficult dungeons with the help of the very souls Majora has created. It doesn't dare try and change what has already happened, changing the people Link has met, or else it would ruin the plan, so instead, Majora makes the world become less and less sane. Take the Stone Tower Temple, for instance. The last temple Link visits, and it defies all laws of physics. Reversible gravity. A mask that makes the wearer a goliath. Flying antlion worm creatures the size of buildings. But this still fails to break Link's sanity, and he retrieves the fourth and final mask to his "challenge".

>all these people saying this is Majora
Isn't this the thing from Dnokey Country Kong?

The mask didn't expect him to make it this far, and panics. When Link enters the Moon, it performs the most dangerous possible move - allowing Link into Majora's own twisted mind. It hopes that by exposing Link to the unbridled force of its madness, Link will crack and give up. However, from inside, Link can also slay Majora. The mask decides to try and weaken Link by taking the masks of those that Link has helped, taking away the mementos of help and love that Link has received, and in return, giving him a useless mask, one that bears no power whatsoever. But Link gains power. He is able to control the world around him, and by donning the "useless" Fierce Deity Mask, he overpowers Majora's madness and turns the world into one of his own imagination, subduing the beast with its own power. After it dies, Link is transported to Termina's surface, where he greets his subconscious image of HMS, Tatl, Tael, and Skull Kid, before walking off into the distance and ultimately waking up inside the tree with a useless mask on his face.

(end)

>Who is Vaati?

>Who is Zant?

>Who is Demise?

>All you had to do was play the Bongos and Majora would have killed himself

wew lad

No wonder they made it non canon

they didn't make it non canon, it was never canon to begin with

it was just the manga author's (the whole who made the officially liscensed MM manga) personal headcanon of how he'd do the origin story if it were up to him

>Termina will never be relevant again

>We'll be stuck exploring Hyrule forever

Pissed off ancient hairy dragon thing that's soul got bound to a mask.
The mangas do a decent job of filling in the backstory in a lot of Zeldas like the war that took place before OoT and where Link came from and so on.