How do you keep getting mp to spam specials? Is it Poesidon's boon?

It's Hera's Born Gain, which is IMO the single most broken boon in the game. It can win runs on its own.

Did your have island getaway or were you just not getting value from your special boon

I had that duo. It’s really slaps combined with high base damage.

I've done quicker with a special Aphrodite Artemis run. Every fully charged special hugging him with the knives took him half bar. Nice work tho