At last! I'm happy to say this unit is complete. This last addition had to be a musician, a self-imposed constraint on each of my regiments.
The mount is the same M22 armoured boar, and the rider an MM90 dwarf. I suspect it's a recast, as the armour details are a little blurry, and the upper part of the blade was missing. I had to replace it with an AoS Kruleboyz spearhead, and swap the left hand for one from an AoS Chaos warrior holding a horn.
So what's next? Well, frankly I don't know. I have more than thirty MM90 Chaos dwarfs left to paint (including 7 models that aren't part of the current army), and the prospect of painting an entirely new regiment isn't exactly exciting (to say the least...).