In the "Gate's of Athens". When you defeat the first medusa you are trapped in a room by aphrodite's image with some mino respawns.

Max RED ORBS here!!!! It can take a long time.

Mino-mini-game (health)
High hits combos (red orbs)

There are 3 minotaurs that will respawn and your magic (Blue Orbs) keeps filling. Switch to Posiedon's rage (right directional button). Kill the min's with Poseidon's and combos and enter the mino-mini-game to get health.

When you get the L2 + O-tap, you can stand in between two respawns and just repeatedly chain. they'll pop and get slaughtered.

Use sword hits and the mini-game to allow magic to charge or just move/dodge until it is charged enough for a Poseidon.

Get 200 hits for +PITILESS, +200/300 for + GODLY, and +300/400 for +OMNIPOTENT. You'll Get 20,40,50+ red orbs respectively. The key is to kill all min's with medusa's gaze. don't do that until after you've maxed everything and gotten a lot of extra Red Orbs for your future magic.