The music it self is not mine so i don't claim that.
It is Paragon9X Chaos C.

Here is the lyrics:

Mario and Luigi, into one big journey.
And their friends, will help out just because,
One great evil have, come to conquer the world.
So they have to join forces, to beat this "last brother".
Mario and Luigi, go to the end, to meet their "Last Brother", and give him one beat up.

"last brother": Hahahaa! so you seriously though you could defeat me? Well your wrong.
Mario: No! We will not escape from you!
Luigi: Yeah! We wont stop till the very end!
!Last Brother": Hahahaa! How pathetic! Well if you are so destined to die then face me.

Mario and Luigi, into one big journey.
And their friends, will help out just because,
One great evil have, come to conquer the world.
So they have to join forces, to beat this "last brother".

Ganondorf: They are amazing! Never though they were this strong.
Pit: Who could have know? Of all this time.
Metaknight: They are... they are...
Ike: Losing.

Mario and Luigi, into one big journey.
And their friends, will help out just because,
One great evil have, come to conquer the world.
So they have to join forces, to beat this "last brother".
Mario and Luigi, go to the end, to meet their "Last Brother", and give him one beat up.