Beat GS:TLA Read the ending text, he becomes the ultimate adept.
Beat GS2:TLA Read the ending text.
Isaac gets all the adept powers, and inherits the power to control the galaxy,
Thats why Issac could beat Sephiroth, With djinn or without.
What? The ending showed Alex absorbing the powers from the 4 beacons and the game ended with him gaining some uber power. I haven't seen these claims you're making and I doubt there would need to be a GS 3 if the main character could control galaxies and what not. Can you prove any of this?
Well your brother is lying. GS is meant to be a 3 part story, and at the end of 2 [SPOILER - highlight to read]: Alex absorbs the powers from lighting the 4 beacons and he appears to become incredibly powerful.
In the end Alex dies lol, he gets so filled from the wise one he dies, notice he says he cant move, and the wise one says he was a fool, the power of sol went to someone more diserving, and he says he gave it to Isaac. Beat it again and read it or look it up.
Now I really think you're lying about a few things. One it isn't stated if Alex lived or died. Also it said a portion of the power went to him and nothing was stated about being able to control a galaxy or anything. I don't even believe that they have acknowledged that space even exists in the GSU. The Isaac you speak of is featless and has not shown any new abilities with these powers so you can only speculate what he can do without actual proof.
Alex is paralyzed and stranded on a collapsing Mountain, Im pretty sure he's doomed, Also, If you read anything from the games, Sol is the ultimate sorce of power, And the Wise one Entrusts Sol To Isaac...
The adepts have some nice durability and Alex is an adept as well so I wouldn't be surprised if it did kill him. Alex isn't confirmed to be dead soooooo yeah. The ultimate power of Weyard has no feats so you can't say how powerful it is.
Lets see what GSS Brings, lol, If he lives, Im certain he will be a villan, due to the fact he abandoned all of his comrades to get the Golden Sun/Sol, and Failed, So Isaac ended up with it.
Isaac and Garret appear to be in the new one, some other girl too, Maybe its a Prequel or a remake?
Prehaps a remake of GS1 With a diff story/Characters..