Attack 13
From the beginning, Xavi's goal wasn't survival or aiming to kill Kil. Xavi knew he couldn't win against that monster, so Xavi at least wanted to chip as much power as possible away from Kil. The last power orb Xavi drilled into Kil's body made sure that Xavi's life force was at constant war with Kil's.
If Kil didn't purge Xavi's lifeforce, sooner or later, Kil wouldn't be able to use his power and eventually die. What Xavi aimed for was to make Kil as weak as possible, so that the others could kill him.
Kil felt the desperate lifeforce of Xavi's inside him swirling around. Blood ran down the sides of Kil's mouth and he had to steady himself, "Not bad, little boy…" Kil coughed, "I give you credit for victory…"
Kil looked down at Xavi, the bloody and gaping hole inside of that little boy's fragile body that almost severed his upper half from the rest of his body, and was sure the young boy couldn't hear him anymore.