Grieving
Handling two kinds of mana at once, on two different patients, was the hardest thing Lith had ever done. He had to repair all the injuries in a timely manner, using darkness magic against the wounds the Valor's life force caused, otherwise his companions would die of shock or organ failure.
At the same time, he couldn't relieve the pressure on the black mass, not even for a second. It was already only centimeters away from their cores, a single slip up and everything would be lost.
The memory of the kid dying in his arms during the plague was still etched into Lith's mind.
There was no way to repair a broken core. Lith only had one chance and had to make it count. His energy reserves were constantly depleted by his endeavor and replenished by Invigoration, but with every cycle, his breathing technique would lose part of its effectiveness.