Some changes, and some progress.
Lava on the base actually looks like lava! Two coats of Golden Yellow followed by two coats of Sunburst Yellow and all we need is a bit more orange splash onto the walls to look like glow.
Next, the banner finished. Went for a palid, dead flesh on the majority of the head, and then my bone triad for the three skulls and the horns. Think it turned out pretty well.
Next, we went a completely different direction with the weapons – ‘blackmetal’ core fading through blue to white at the cutting edges. IMO, this looks much better and less cartoony than my previous attempt.
And, the finished model, with a slightly different more relaxed “surveying the field” pose.