Confronting this soul as dark as the abyss that demons climbed out from, Rino finally understood why the necromancer called him young.
He was simply too inexperienced in dark arts.
The magic tree's soul was a cauldron for stomaching many souls and absorbing suffering from charmed souls. Using the knowledge, memory and experience of these poor, unfortunate souls, the magic tree fed on their darkness to become a sinister existence that craved carnage.
Rino should take a leaf out of this mean existence to learn how to be a better lich. He thought that dark magic was used to manipulate shadows and consume souls. He did not think that it could do much more than simply torturing them for mana regeneration and increasing his mana capacity. Those soul contracts he made the fairies enter into were work contracts with their souls bonded to World Tree Rino for mutual benefits.
Reader Side Quest:
Guess the meaning of Ubel and what language it is.