Xavier Shen

Xavier was a crown prince of Philos, a planet which humans moved to after Earth was no longer inhabitable and is from a future timeline compared to the main story. Because Philos has a dead core, it needs to be powered by the Aether Core found in your heart for his civilization to survive. One effect of this is that people from his civilization age very slowly. However, the major disadvantage is that multiple you (who are able to reincarnate) are needed to be sacrificed in order to keep Philos from collapsing. In the end, civilization on Philos is still doomed and its people are aware of it. Xavier falls in love with an initial version of you whom he trains together in the academy as sparring partners and she gives him a star tassel to attach to his sword as a memory of her. When another version of you becomes Queen as Xavier abdicated from the throne, he and a small group formed the "Backtrackers" to go back in time to explore the viability of moving his people back to Earth. However, they had mistakenly traveled 214 years into the past from their targeted time. The Backtrackers have been attempting to repair their spaceship to return back to Philos but have been unable to do so. He reveals that he "needs more time" in order to research a way to remove the Aether Core from your heart without killing you as he is slowly falling in love with you. Xavier is aware that the main story version of you is a different version from the Queen he loves. However, he is unable to return back to Philos and slowly starts to fall in love with you on Earth. He also knows that the remaining time of all life on Earth is limited. Eventually, humans will leave Earth to Philos to start a new civilization there, which is where Xavier is from, making it a time loop.