I'll explain it.
RED: "Energy" in %. It makes it more interesting if you don't know the exact value. Also, the battles are so fast paced and heated that you don't have time to think about numbers. Just seeing the bar shortly you will realize if you need healing or not.
GREEN: "Lexima Power" which is something like SP, also in %. LP are being recovered with time and are needed for skills and the such. LP are also needed for charging up attacks. i.e. If you plan on attacking an enemy with a charged attack (yes, you can use normal or charged attacks), you simply hold down the button. LP is being consumed until the maximum charge power is reached or until you run out of LP.
YELLOW: "Combo Efficiency Charge" in %. When you use a combo, the bar is being filled up with each hit. The more the bar is filled, the more damage each hit does additionally to the base damage. If you get hit by an enemy, you lose CEC. each attack from enemies takes away a specific amount of Energy and CEC. Of course there is a divergence so it's not 100% the same each time.
BLUE: "Battle Style Charge" in %. The better you fight, the more filled is this bar. Executing an action twice decreases the BSC. Getting hit decreases the BSC. Being interrupted during a combo sequence decreases the BSC a lot. Having it filled as much as possible is necessary because it multiplies the weapon EXP and skill EXP you are getting up to 3 times (full bar).
I'm still thinking if I should let the player start with a half filled BS bar and if I should make it so it decreases with time as well. I'll see.