Since this question wasn't addressed in the insider or errata threads I'll ask it again here.
Since PP believes Spell Slave does not need to be fixed, what is your stance on Mortenebra? Is she currently working as intended, or is how Derlyss interacts with her spell list being looked at? Because while I understand not wanting the Skarlock Thrall to become an auto include with all Cryx casters, Derlyss is a literal auto include that Mortenebra pays for, and doesn't want because he's lost all synergy with her spell list, and is generally an overpriced Necrotech or a use of Sacrifical Lamb. Derlyss can't cast half of her spell list. Casting Overrun currently does nothing. This leaves him with the ability to cast Doom Spiral, which is just a terrible nuke when you can't boost damage, and Void Gate a spell that's next to impossible to actually get value out of.
If Mortenebra & Derlyss are in fact working as intended, what exactly is Derlyss's intended purpose? Because when I look at them I can't see it.