Practice Dummies
Like the chimera ants colony, different ants performed different functions.
Ulric, Gadu and the last Werewolf were unlucky enough to have met creepy crawlies that fed on human emotion. To be precise, they fed on a mixture of joy and good memories.
Their piercing mandibles taking huge bites out of their precious memories.
Lenny left them in this place to suffer for many days while he had other experiments to perform.
Of course, those experiments involved increasing his strengths with runes and bitter cultivation.
To lenny's surprise, he discovered that he could practice his rune crafting inside the Satan System as long as he had sent the materials into the storage.
Naturally, he used the training ground for this