The Triforce is one of the most ancient artifacts of all ancient artifacts. It is so ancient, and so artifacty, that there are legends surrounding its ancientness and artifactyness. It is also very shiny and triangley. Contrary to popular belief, there are actually five triangles, not three.
The Triforce was first created by the greater gods. By the greater gods, we basically mean Tom found some Chaos Energy, thought it was Chocolate, and tried to eat it. This resulted in the creation of the Triforce. For some reason, it magically floated into Hyrule and now it hangs out there for no particular reason.
Parts of the Triforce
Triforce of DINNER
The little golden triangle on the top is the Triforce of DINNER. The Triforce of DINNER was destined to be wielded by King Dinner. However, King Dinner had died hundreds of years before the creation of the Triforce. It was instead given to his great great great (many greats later) great great grandson King Harkinian, who in no way deserves this power. He only likes it because it is shiny.
The Triforce of DINNER grants the wielder the power to bestow DINNER upon all who the wielder desires. This is an incredible power, as it can end UnWorld hunger and create lotsa DINNER. However, the fool who wields it instead uses it to power his Dinner Blaster.
Triforce of Baby Yoshi
The piece of the Triforce on the left (it is always on the left, even when flipped over) is the Triforce of Baby Yoshi. This piece was formed when Baby Yoshi stole some of Tom's Chaos Energy, and tried to eat it. After three years, Baby Yoshi finally spit up the Chaos Energy and it joined back with Tom to create this part of the Triforce. It is currently owned by Link.
The Triforce of Baby Yoshi grants the ability to turn into Baby Yoshi for exactly 3.141592653589793238462643383279502884197169399375105820974... seconds. Besides that, it is completely worthless. It is so worthless, it is believed Link threw the Triforce of Baby Yoshi in a pot of Turtle Soup.
Triforce of Ugliness
The Triforce of Ugliness is the piece of the Triforce on the right (though it will be on the left if flipped). The Triforce of Ugliness was created when Bob Saget decided to show his ugly face to the world. It was so hideous, this piece of the Triforce was created. The Triforce of Ugliness is "the stupid piece". It is called this because it is stupid. Ganon uses this piece of the Triforce.
The Triforce of Ugliness is capable of turning the wielder into a hideous beast. The only problem is that it can not change you back. This is why Ganon is so pissed off all the time. Besides that, it is also good for scaring the neighbors.
Triforce of Thin Air
The Triforce of Thin Air is literally just that. It is the non-existent triangle that lies between the three gold triangles. It was created by Nobody, and Nobody still wields it to this day. The Triforce of Thin Air has no special powers or any reason for existing other than to fill the space between the other pieces of the Triforce.
Triforce of Triforce
The Triforce of Triforce is the creatively named triangle that is formed when the previous four triangles are put together. When put together, the wielder becomes as powerful as WaPo. This has only ever happened 42 times before, and 41 of those times was because of Link doing it on accident.
Triforce of Wisdom
The mythical sixth piece of the Triforce is the Triforce of Wisdom. The rumor first started when Zelda was given a piece of the Triforce by Rick Astley. She proclaimed she had the Triforce of Wisdom, but Nobody believed her. Nobody believed her because even an idiot could see it was a cardboard triangle with "I am a triforces" written on it in crayon.