Soul force and Light Force

A short while later, Derek stood before a really deep crater. Beside him stood the mature beauty with long golden hair, while his wives and the others were behind him.

There were no buildings around this area, only tall street lamps. "This is where it began. After the world went dark, we lost connection with the rest of the world, causing us to struggle to defend ourselves from the night beasts. Our population gradually decreased from hundreds of thousands to tens and even lower.

Natasha spoke gently toward Derek as they walked down the deep, dark hole with the others. 

"When our numbers fell to a critical point, we nurtured the thought to take refuge under the federation, but you came," Natasha paused when Derek raised his hands.

"I came? That's not possible; I don't remember ever being here," he said.

"Fufu, then who's that?" Pointing at the distance, Derek and his curious women gazed at the distance but saw nothing except darkness.