Spoilers: Character background and the premise of the Chaos Dwarf campaign; no campaign ending.

The High Priest of Hashut
Astragoth stands at the head of Hashut's priesthood as its High Priest. He is the oldest living Chaos Dwarf Sorcerer-Prophet. Once a far more powerful sorcerer, he now faces declining magical strength and the petrification of his body.
The Forge introduction places that earlier strength on the Plain of Zharrduk, where he was once the most potent sorcerer. Prolonged petrification is what has worn the power down. In battle he remains an armoured caster of Fire and the Lore of Hashut, able to fight up close, and the device that moves him is fast for a body in that condition. Among the Dawi-Zharr he is the lord who draws more Conclave Influence in the Tower of Zharr.
The machinery behind the name
His legs ceased to work as the petrification advanced, and his hands also turned to stone. A mechanical frame restores movement, while machinery replaces his hands. His thralls built these devices to his designs, joining Chaos Dwarf engineering to his sorcerous knowledge.
Astragoth in Warhammer III
In Immortal Empires he leads the Disciples of Hashut. The campaign gives the High Priest an industrial empire and rivals competing for influence in the Tower of Zharr. In The Realm of Chaos, the Chaos Dwarf story instead centres on constructing the Great Drill of Hashut. These are campaign premises; the wars and alliances that follow depend on play.
Astragoth Ironhand: gameplay and availability · More character stories
Sources
- Introducing Astragoth Ironhand — totalwar.com
- Forge of the Chaos Dwarfs — support.sega.com