Ike runs the gauntlet
It's Ike in the end of Radiant Dawn, meaning at the peak of his power we ever saw. He is NOT healed between these fights, but he gets a minutes rest between them. They got no knowledge on him, he got no knowledge on them.
1: Pokémon Trainer Red (Gold/Silver Final Boss)
2: Mario, Wario, Luigi, Yoshi, Bowser
3: Twilight Princess Link (Full equipment, no Midna)
4: Ryu & Ken
6: Jinpachi, Heihachi, Kazuya and Jin (Devil forms allowed)
7: Akuma (Shin Akuma allowed)
8: Midna
My own opinions?
1: I doubt Ike would be able to take out all 6 Pokémons, but it really wouldn't matter, as Ike would just use his superpowered jumping and speed to quickly get behind them and kill Red.
2: Ike would have trouble, especially with taking out Bowser's durable body, but he would win with little to no damage.
3: Link got strenght comparable to Ike's, but a helluva lotta more equipment. However, Ike is definately the more skilled and faster swordsman, and I believe he would defeat Link, but it would leave him exhausted and damaged.
4: Together, Ryu and Ken should be more powerful than TW Link. However, I don't feel their fighting styles would be good match-ups against Ike, and I think Ike would win without taking further damage. I don't see them defend against his attacks.
5: I forgot a 5, lol.
6: Ike is damaged from previous fights, and even if he wasn't, the devil forms would put up a hard fight. It's a 50-50, with Ike MAYBE BARELY being able to win. The lasers and telekinesis would be real problems.
7: The damage should be too heavy on Ike. He would be able to fight back, but would soon lose.
8: Ike wouldn't reach 8, and if he did, Midna's strange powers would completely overpower him.
If you don't know Ike, then this should make it clear to you about how powerful he is:
Normal, trained soldiers are more powerful and skilled than your ordinary fighter. Trained laguzs, like Lethe, Mordecai and Ranulf, are able to take down like 10 soldiers in seconds. Black Knight, however, defeated Ranulf with no trouble. And Ike defeated Black Knight after a hard and even duel. After that, 3 years passes and Ike is now even more powerful! Not only that, the godesse blesses him and he becomes a Vanguard, getting a massive boost in power. He even defeated a now stronger Black Knight and was at ease afterwards, walking like nothing happened. Of course, Black Knight did put in up a fight, as the cutscene suggested.
Basically:
Normal man <<< Normal soldier <<<<<<<<<< Elite laguz <<<<<<<<<< Black Knight < Ike << Ike 3 years later < Black Knight 3 years later << Vanguard Ike