tl;dr

Yu Lian is the child of Changxi, born in the mortal realm. He returned to Heaven and serve the Xing Guan, as the new moon deity. But he didn't live long as he was assasinated by the heavens traitor.

Min Yu Lian was born as his injured mother sheltered from a vicious storm caused by the Thousand Year War. She had traveled from a distant land. Exhaustion overwhelmed her on the eastern slopes of the mountain, and there, beneath cold, pitiless moonlight, Yu Lian came into the world as his mother breathed her last.* As the storm abated and the sun reached it's zenith, hunters from the nearby temple found him, alone and wrapped in a silver cloth. They brought him to the temple, where the foundling child was presented to the monks and named Min Yu Lian. The child with the sable hair was raised as one of the temples, a faith that dominated the lands around the mountain. Min Yu Lian was taught and raised by the temple elders. He learned how to sing and dance, how to play instruments, how to heal the wounded. He was presented as the treasure of the temple. Min Yu Lian would always find moonlight entrancing and beautiful in a way nothing else could never match. Every night the young child would wake from dreams of climbing the mountain to sneak from the initiates dormitories to pick night-blooming flowers and dance in the moonlight. One late evening Yu Lian decided to climb the mountain. He climbed for hours until he was above the clouds and in the chill air where the moon and stars glittered like diamonds. Eventually, Yu Lian fell to his knees, exhausted and weary beyond imagining, his entire body strained to the limits of exhaustion. When Yu Lian looked up, it was to see that somehow, he had reached the mountaintop.

The moonlight surrounded Yu Lian. He felt a union with something vast and inhuman, impossibly ancient and powerful. The sensation was painful but also joyous. When the light faded, the cave mouth became visible. Yu Lian sought refuge within the cave. Inside, the narrow cleft widened into the crumbling ruin of what might once have been a temple or vast audience chamber. It's crumbling walls were painted in faded frescoes depicting warriors of silver and gold fighting back to back against an unending host of grotesque monsters as the sky rained comets of searing light. At the center of the chamber stood a crescent Ruan and a silver cloth with gold and silvers on a Lotus-shaped silver plate. Reflected in the gleam of the shining temple walls, Yu Lian saw his once sable hair was now purest white, and a rune shone on his forehead with incandescent light. He recognized the symbol so exquisitely etched into the Ruan. As Yu Lian reached his hand to touch the Ruan, his vision faded. Clad in shimmering gold and silver, the cloth in the color of winter snow at night, Min Yu Lian is a living embodiment of the moon’s power. Imbued with the essence of an Aspect from beyond Xīng Guān towering summit, Min Yu Lian is not wholly human. He is Changxi’s son, one of the twelve moons. He has been taught the power of the twelve moons. Min Yu Lian lived within Xīng Guān protection during the Thousand Year War... until the night Xīng Guān fell. It seems one of the trusted guardians has betrayed the heaven realm. Xīng Guān was destroyed and Yu Lian was erased from existence.