The thing is, what's the motivation to chase down Illberd? Losing an arm? Corruption? That's not quite enough, considering he's essentially just a thug with a dream now. Nanamo dead at least had Raubahn fueled by some lover's rage. Him being severed from Lolorito took any of the threat he possessed to the WoL.
(Also it's obvious Raubahn doesn't care that much about Ala Mihgo. He's got a new home and new family.)
Why should we care about Ilberd? I see him making some stupid pact with demons and getting killed off. His two lackeys were more interesting considering you tried (and failed) to reform them.
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