Hmm.. fire + earth = Hermes, fire + gravity = Graviton, fire + water = Harmony? I hate explosion and creatures with growth ._.
The octopuses seem a little redundant, there are already 12 fire lances, inundation, and permafrost. Neptune needs octopuses because shockwave is only instant kill if the creature is frozen, while with enough quanta, fire lance will always kill.
Eight probably isn't enough creatures for damage though. Yes, 15 health is hell for otyughs, but they can be taken down. And there isn't any guarantee of drawing them fast enough. Maybe toss in a few dragons or rage potions to get that damage up quickly. But then it might be too similar to Hermes.
I don't think Harmony is very fitting with the deck. Maybe something like Raging Tides. Sounds stupid for a name though.