So... On the Purple Sun warscroll, it says if a unit is touched by its rays then roll XD6 where X is the number of models in the unit and for every 6+ a model is slain. But if the models have 6 or more wounds they takes 2D6 wounds. Lets say the Purple Sun touches Lord Kroak. He has a wounds characteristic of *. Is * more or less than 6? Would we roll one dice and lets say we get a six so he is dead (but not dead because of his rule that he takes D6 mortal wounds) or does he take 2D6 mortal wounds?
he does not have more than 6 so that trigger doesn't happen. rules like that check the flat value on the warscroll. on the 6 he would suffer an instant death effect. kroak rules instant death as 1d6 mortal instead. My answer is 1d6 mortal
This seems like a trick question. Unlike other Slann, Lord Kroak is already dead..? Broader question: why would The Purple Sun further harm any units which consist of dead things? Ghouls, Zombies, Skeletons, etc.
Mainly gameplay reasons. The word 'slain' is defined as removing them from play. My fluff: the Purple Sun disrupts the necromantic energy that makes them undead, and transfers them back to the realm of Shyish so they are destroyed here. Same for Kroak, he is weakened by it so he receives 1d6 wounds (as specified by his warscroll).