When Ragnarök descended, Yggdrasil entered its life cycle. After all, it was a tree by nature, and trees withered and flourished. Its cycle was simply much longer.
Asgard, where its roots were located, had no way to escape and ultimately fell into Alaska. The other eight realms, however, were like leaves on a tree. As long as they broke away from the branches in time, they would naturally be preserved.
Earth had Deathstroke and Kamar-Taj, so it naturally stood firm as Mount Tai. Besides, it had only been counted among the Nine Realms to make up the numbers. Yggdrasil's influence on Earth was extremely limited. Strictly speaking, this place should have been Vishanti territory.
Vanaheim had been teleported into the Spectre Universe and was still intact. Jotunheim, meanwhile, had Angerboda looking after it, so the Frost Giants had naturally weathered the crisis as well.
Both places belonged to allies. Trolls were like earthbound rats, but they clearly would not be hiding underground in either of them.
Vanaheim had vast oceans and countless rivers, with all sorts of bridges everywhere. When Trolls saw a bridge, they simply could not restrain themselves. They definitely would not have the patience to stay cooped up underground.
Jotunheim was even simpler. Its boundless ice fields were filled beneath the surface with Angerboda's pet giant maggots. Even Frost Giants did not dare scurry about underground.
The fire demon Surtur's Muspelheim could be considered Hell. He had probably taken his kingdom and hidden in the Splitting Domain back then. Hela's Underworld Heim was much the same, temporarily attached beside Magik's Limbo.
Neither place was suitable for Troll survival. Their concepts were fire and death respectively, both exceptionally unfriendly to creatures of flesh and blood.
Next came the Dwarves' kingdom, Nidavellir. Yet it differed from the other realms: