Collapse of Iron: the Promise of the Spark Prism

[Honkai: Star Rail]+[Ultraman Tiga] "Long-form + main line adapted narrative" Due to something happening, Lu You lost the ability to transform into "Shining Tiga". In the battle with the final BOSS, Dark Lucifer, Lu You, who was forced into a desperate situation, planned to give up his identity as a "human" and 100% integrate his free will with Tiga, the god of light. But at this critical moment, her sister, who had been dead for a hundred thousand years, used her last strength to throw Lu You into the Star Dome Railway Universe, one of the thousands of "sub-universes". Due to the different speed of time, Lu You needs to regain the ability to summon "Sparkling Tiga" in that not very generous time. So, after witnessing the survival of Bengtie Universe with his own eyes, can Lu You complete his self-salvation?