In the beginning of the 19th century, Rainbow-face lived in a log cabin with his parents in an isolated forest. They loved each other to death and each member of the family had a role to play. His dad (John) was a wood carver who often went long ways to town to sell his artwork, his mother (Eli) was a housewife with a skill for cooking, his little twin brothers (Henry and Arthur) were young, naivee, and utterly adorable, and Rainbow-face brought joy to his family with his drawings.

At a very young age, Rainbow-face was an extremely skilled artist. He loved drawing sceneries with his family in the middle of it. Always smiling, always with a happiness that didn't stray from reality.

However, things didn't stay happy forever. All of a sudden, a famine came over them. The soil they used to farm was abruptly horrid to use and the animals nearby seemed to have just disappeared. They were hungry. Extremely so.

Eventually, winter came. The famine had not left. One night, John took Rainbow-face out, claiming that they were going to make a quick trip to the nearby town to sell some more of his wood carvings. Rainbow-face, who hadn't been to town often, was extremely excited despite the cold and despite the hunger. He brought his sketchbook with him, planning to draw the town and his family as the main center of the piece as always.

But as they were "halfway" there, John remembered that he left a piece of art at home. He told Rainbow-face to wait by a tree and that he'd quickly go back home to get the piece. The night wasn't that cold and it was already bleeding into autumn. Besides, Rainbow-face was 17 at the time, he believed he could handle it. And so, he sat down on a rock nearby and drew as his dad went back home.

However, as the night drew on, Rainbow-face began to worry. His dad wasn't return and the forest was starting to look the same in each direction. It was dark and every noise scared the living lights out of Rainbow-face. Shaking due to fear and hunger, Rainbow-face got up and began walking, hoping he'd see his home and return for some shut eye. But, the more he walked, the darker it became. Rainbow-face couldn't see a thing and panic surged through him. He began running and screaming in a desperate attempt for literally anything to find him.

Branches scratched and scraped at his coat, causing Rainbow-face to loose it in a moment of sheer terror, leaving him in a thin shirt and a scarf his mother gifted him before he left. Eventually, Rainbow-face collapsed. Hunger and exhaustion wore him down and he died underneath a naked tree, darkness being the only thing he saw before death.

Years later, he awoke as a spirit in the middle of Easter. It was bright. The sky was blue and the tree he was under provided shade with its leaves. At first, Rainbow-face was absolutely terrified of his new surroundings. He didn't remember a single thing and everything around him was new. After a while of wandering, Rainbow-face found a few kids along with who he assumed to be their parents. He tried to interact with them, but couldn't. Some time later, Bunnymund found him and decided to take him back to the other guardians, seeing that Rainbow-face was scared and obviously not normal at all.

To summarize- They go to the North pole, Rainbow-face gets accustom to living within North's workshop and kinda just..lounges around, drawing abstract pictures with no real meanings behind them. North is like a father figure to Rainbow-face even if he won't admit it.