Aside from things like souls and mana, Classes were also a universal concept. They weren't a prospect only for worlds. Even the Undead had them.
Undead Infantries, Undead Captains, Death Knights, Calamity Knights, Doom Knights…
These were all Classes, but unlike on Aigas, the term Class when it came to Undeath did not solely represent an area of specialisation. It denoted a mixture of rank and purpose.
And indeed, Death Knights, as Undead units, had a purpose. That was why there was a precise formula for creating them known to all Lichkind.
Sila's opponent, newly born, was just getting a hang of its purpose.
