Collapsing Eternity (Part 1)
Thaymos' strength turned into poison and his enchantments shorted in a rainfall of wild mana sparks.
The colossus fell to the ground, incapable of withstanding his own weight. The Life Maelstrom coursed through the Eternal Fortress in a cycle of destruction and regeneration that drained his mana reserves.
Tyris made it even quicker by dropping Morning Star on his chest. Without the ability to conjure a hard-light construct, Thaymos' hands melted as soon as he grabbed the haft.
In the span of a few minutes, the living castle was reduced to a pool of molten stone and stayed that way. All the mana the lost city had accumulated since his creation was spent and what was left of it was barely enough to keep his pseudo core from succumbing to the heat radiated by the mace.
And that solely because Tyris willed so.