Mihila couldn't get life essence for Kayla because it is very valuable and rare to encounter. The problem is that the supply is limited while the demand is nearly unlimited. Everyone wants life essence but they can't have it.
Even Sovereigns of law need life essence for the tribulation to become Origin gods. So how can a weak mana entity with the help of a titan of law get it? However, he can get as much as he wants as a Supreme beast. Access to Life essence is his birthright. He doesn't have to kill or pay for it. He just has to place the order and it will be brought to him.
The ease by which he could get something like that made him shake his head in wonder. "They must have life trees planted somewhere. It is the only way that they can match high elves in the amount of life essence they can provide."
I've started a new book titled DESTINY GAMES. Please check it