I was thinking about Khan too, because Khan and Ferrus Manus should switch sides. Khan as prince of Slaanesh and Ferrus as decaying servant of Nurgle, why? - The White Scars are always about swift and fast attack, ready to hunt like an eagle, to be perfect in hit and run tactic, they just contribute a lot of desire for perfection. They would be great to show elegant, but deadly combat under Slaaneshies banner. On the other hand (pun intended): Iron Fists fit into Nurgle, because they discard their flesh as something of failure and decay, they want to augment themselves, but it is just to be able to fight. Better weapon or new pair of mechanical legs, but flesh is unimportant, so they want replace everything (smth as mechanicus cult). The price for wearing metal is high, therefore they rust and spread Chaos virus (bio or digital chaos corruption).