Underworld

Deep underground, Cantish open their eyes to what may as well be a second life. They are reduced and shaken, but alive in a strange buried city. They gather and piece together what happened: the smaller golems evacuated all they could down through the earth. The totems activated not only the defenses above ground, but the greater ones down here too. They soon find old scrying bases and a miracle - the voices of other lost Cantish through the crystals. There's not one city but four: Riag in the north, Dorel in the south Kandaren under Cantor city and Telurus, capital of Telurea, in the east. All survivors were taken to the one closest to them.

Those in Dorel hear another, unknown voice from the crystals. They respond with caution that quickly flips to disbelieving excitement - it's a scryer from Nisalvini. Word and wonder spread quickly. Both sides begin to dig with the help of Nisalvini's new resources and Dorel's golems - and soon, in a matter of days, they breach the rock separating them. The people lost under Alva have found each other.

A new quest begins to explore their surroundings and reach those above ground. People flow between Nisalvini and Dorel and marvel at both. Others search through Riag, Kandaren and Telurus. A few journey to connect all cities, using golems to carve through stone. As they do, the earth around them changes too. Tree roots break through the dome cases and bud with leaves, forming new, inverted branches. Natural energy descends and dormant seeds in the caverns begin to sprout. The heart of Cantor lives.

You can contribute worldbuilding for Riag, Dorel, Kandaren and Telurus this prompt - guidelines here!