(3rd person POV)

   The hole Underground rejoiced. Twin skeletons were born into the royal family that day. After being sealed under the earth, the last remaining skeletons had taken the throne. The war had nearly killed all the skeletons because thay were the first to the battlefield, first to protect another from humans. Skeletons had a natural instinct to protect, making them good generals and leaders. Only two skeletons made it to the Underground before the barrier trapped them all down here. The few left on the surface were killed soon after. The skeletons names are W.D. Gaster and Night-Bird. They were soon selected to be the new king and queen of the Underground, the previous king had fallen in battle.

   It took a good 10 years, but the Underground was turned into a real home home for the monsters. Soon after that, a human child fell into the Underground. They fell into the ruins, where the monsters were first living. In order to one day break the barrier, they needed seven human souls to counter the seven wizards who created the barrier. The child thought they were above consequences, and killed multiple monsters. Gaster fought the human, and took their soul. This repeated until the kingdom of monsters had four souls. There then was peace for many years.

  Twins were born, two sons of W.D. Gaster and Night-Bird. The fist born's soul was green, that of kindness. The younger was born with justice in his heart. The oldest was to be king, but he was introduced as the youngest, because of a few reasons. One of his legs cracked, and he would need to use a staff to support his weight for his entire life. He was also blind in one eye. Gaster thought it was best if there younger son with the stronger soul of justice, ruled one day.

The two brothers grew without knowing the lie. Besides their parents, there was only one other monster who knew the truth. But he was loyal to the king, and wouldn't tell. When the twins were three, another child was born. This one had a light blue soul for integrity. The three brothers were the closer then you could ever imagine. They loved each other, and there parents. Peace settled over the Underground like a blanket. But nothing lasts forever.

Sans, with the soul of Kindness
Papyrus, with the soul of Justice
Zeke, with the soul of Integrity