Da Tang Shuang Long Zhuan - Book 61 Chapter 3 – Waiting for Dawn

[Congratulations! You’ve unlocked the Dimensional Motel System.][First Mission: A runaway princess—hailed as the most beautiful in the land is being hunted by her step-mother. She was originally headed to the dwarves’ cottage, but the System has rerouted her to your motel instead.][Protect her. Win her trust. And if you manage to woe her, you’ll earn her Affection Points.][Bonus Mission: Sleep with her evil stepmother to unlock more reward]'What kind of weird mission is this? And why does this story sound way too familiar?'

Struck down amid the battle, the Hero and Demon King meet their demise. As their souls linger on the edge of the afterlife, a mysterious force intervenes, merging their fragmented souls together with a new being. Rusty, the living armor, now affected by their memories and presence, embarks on his own quest. Will he seek revenge on those who betrayed the hero, or will he fulfill the desires of the fallen demon king? or instead, forge his own path?

I lived for you in the last lifetime, everything I did was for you, yet you wanted me to die; so, this time, life is mine to live! This world lied to me, betrayed me, and humiliated me, and I am back to change everything!

- Description from Novelupdates

Zhang Gong decides to learn light magic, a magic few show interest in and eventually becomes the legendary Grand Magister. While trying to end the continent’s east and west separation in order to unite all of the different races, he becomes every race’s Child of Light.