Alm and Bruno gathered all the hundreds of black elves present. Then, they talked to their elder. They learned that everyone lived together, using the weaker demonic trees as their homes, offering something to nourish them in return. It was a mutual exchange, and the elves could live relatively safely. So, they offered a better alternative, and everyone promptly accepted.
They erected a dozen earth buildings in minutes. Soon, underground tunnels were made, connecting all the buildings to a distant place. This way, everyone could live there. The earth's defenses were like divine steel, thanks to the Behemoth lineage. Even if something happened, they could escape through the tunnels.