Cool concept, I can tell a lot of love and care went into this. There is definitely something here if you wanted to keep noodling on it this could be a great battle system in a larger game.
There was some language I didn't really understand, and I never really knew how much damage I was doing or would do, or take, and how much HP I or the enemy had. But I think those are things that would be pretty easy to clarify since you have that information on the back end.
I never really was incentivized to use Obs except to heal in my play throughs. A few suggestions:
-Having enemies deal damage to your orbs would give a little more incentive to use abilities and give players more expression, and developers more space to tool the monsters with besides raw damage.
-Remove auto attacking and force players to exchange orbs for damage every turn would help orb economy and force churn of the orbs.
-Perhaps certain characters can only create certain color orbs.
-I'd love to see each character's buffs and abilities only effect them individually, and individual life bars, but still share the orb orb pool.
For example, +orbs should only effect the player who uses it so instead of an additional 3 orbs, you would only get one.
Definitely something here, would be awesome to see this become more.