The demons item chaos essence is well.. useless. Unless you have a pool nearby the mid its useless for taking down minis. Heres an idea to make it more used:

Empty Orb
Costs: 1200 lumber, purchase cd is 30 second.
This is a empty orb, ready to capture an essence.
If you have this item and you purchase the Chaos essence you get this:

Chaos Orb
This orb has an chaos essence inside it, when used it increases the damage by 50% for 12 seconds.
Has 2 charges.
And this new item:

Fortificating Essence
When bought empoweres all nearby units in an 500 AoE whit +100% armor for 12 seconds.
If you have the Orb than you buy the Fortificating Essence you get:

Fortificating Orb
This orb has an Fortificating Essence inside it, when used it increases the armor by 50% for 12 seconds.
Has 2 charges.
EDIT:
Removed gold cost on empy orb and increased lumber cost.
The orbs give less bonuses, but they have 2 charges.