Mako stumbled back after he had finished placing the last of the poison inside Bill's body.
Not only was his energy being drained by the system to utilize its emergency healing feature which wasn't very energy-efficient in the first place, but it consumed even more energy to heal another person through simple contact alone.
Alongside the healing, Mako also used his Energy Sensing skill and Memory quite a lot which further drained him of his energy and gave him a lot of mental strain.
Lastly, he used mana manipulation to control the water, which consumed twice as much energy compared to if he possessed the actual Water ability; plus, he also had to spend a lot of mana to inscribe a simple command on each and every bubble to retain its shape and to leak the poison slowly into Bill's system.
By the end of it all, Mako was completely exhausted and was only able to retain less than 1000 energy points.
