Agahnim is Ganon.

[Mysterious F.]

Proof: 1) Take a look at this picture of Agahnim http://hyrulerealm.guardianarchives.com/Official/LttP2/Agahnim.jpg    notice he has claws like Ganon, skin like Ganon, and eyes like Ganon. 2) How else can he use that magic and go to the Dark Realm all the time. 3) After you beat him in Ganon's Tower, you see a faint and short Ganon figure rising from his body before the bat comes. 4) When you fight Ganon, he says "It's unbelievable that you defeated my alter ego, Agahnim the Dark Wizard, twice!"    All together, he's Ganon.

[JDog]

Good point, it does look like him, a little.

[Mysterious F.]

And Ganon said so, which is automatically proof that they're the same person.

[Gamefreak]

I always assumed Ganon was just posessing Aganhim's body for the duration of the game.  But what you said makes sense.

[Marcamillian]

good evidence.. however... this begs the question what the hell was gannon trying to do by kidnapping the maidens? I thought it was to free gannon... bt if gannon was Agahnim surely he's already free!

[ReFried ReDead]

I would consider him a weaker form of ganondorf

[Mysterious F.]

Well, Ganon was probably trying to get the Sages into the Dark World so he can make sure they couldn't go anywhere, seeing as he owns the Dark World, he'd be able to hide them in secure areas. Also, Agahnim is Ganon's alter ego, meaning they're kinda the same person, but with different personalities and stuff.

[Darth Wyndisis]

What is up with the symbol on Agahnim's cloak?  It looks like the Sheikah Eye.

[Mysterious F.]

It could be some dark, evil symbol.

[Gamefreak]

Well there's using your brain.  An evil dark symbol.

[Nabooru]

I like gannon better than him so good.

[Zelda Veteran]

It is kind of wierd. The evidence all points in the same direction, but whats with the eye on his clothes? You should sctually look for that symbol somewhere else. Ill look through the compendium/bestiary to see what i can find.

[Hi no Seijin]

Um, it's spelled Ganon, not Gannon.

Also, I looked up alter ego.  I got:

1:  a second self; a perfect substitute or deputy:  The adviser of the president acts as his alter ego during his absence.

2:  an inseparable friend.

Just because Agahnim is Ganon's alter ego doesn't mean they are the same person.  Besides, Ganon couldn't leave the Dark World, possessing someone or reincarnated.  Agahnim was in the Light World trying to get Ganon to come back to the Light World.  When Agahnim went to the Dark World, he was possessed by Ganon, who was probably ticked off at Agahnim for not killing Link.

[Mysterious F.]

Well take a look at the character Yugi Mutou in the TV show Yu-Gi-Oh! (I hate the show now, but I use to watch it), he has two personnalities, small and shy, and courageous and dangerous. Bakura is also like that. But the extra personnalities are in the same bodies as Yugi and Bakura.

  Also, Agnahim and Ganon are probably not friends, judging by their personnalities, so it must be two, a second SELF.

[MagmarFire]

Okay, but if Agahnim was killed after the second battle with Link, how'd Ganon be able to fight him? I'm saying this as if Agahnim were Ganon.