Before their second visit to the liches dungeon, Leon only had a couple of hundred hundreds of undead Trent branches, but now he has thousands... Keep them stored was a waste of time, so Leon decided to use Mana-Eater and consume those. It wasn't a plan Leon would like to use often, but he could use that skill to tire his opponents out. But to do so, he would have to level up that skill more than a few times. Although Leon could also consume mithril to level up Mana-Eater, it wasn't that efficient, since his mana was used to consume and create the mithril, after all.
After creating the rings, he wanted and several spares, Leon wondered why he didn't obtain a magic item that had the Mental Drain skill. Creating mithril weapons was time-consuming, so he attempted to seal the spirits of the liches in some steel weapons, still, it wasn't enough to obtain the skill through magic items either.
