Ok, the Idea here is the following:
Use, Gigas as your leader, Chaos Dragon, Tyrannos, Echidna, Noel and a friend Amaterasu Okami.
Charge your skills the first round, only kill a knight if its attack is linked with another. If 2 knights attack on the same turn, you could die!
ALWAYS MATCH ORBS, OKAMI ONLY HEALS ON A MATCH!
Use Chaos dragon, Tyrannos and Noels skill to clear round 2 and 3.
Round 4 is keeper of light or dark. With okami and your titan you should not die, EVER!
Just make sure to always make matches.
Round 5 is Rainbow Keeper. It will be PAINFULLY slow, you basically have to rely on ChaosDragon, Noel and Tyrannos to kill him. But you will... after 1-2 hours!