This page holds debatable information that is more or less considered not canon for either of the two timelines.
Upon this route, Solar is killed when a duel against his mother goes awry. During his afterlife, he becomes a shinigami and possesses his corpse as a manner of undeath, while getting used to the job due to his proficiency with spotting weaknesses and taking down opponents quickly, he tires and worries about the life he had left behind due to said death. It isn't long until he makes his move and discards his Shinigami role in an attempt to destroy the timeline, coming to blows against his mother, the Organization, and his newfound employers. Throughout a large and bloody battle, he ends up killing even a few of his own men which put the Organization first, in order to access the Izayoi Tower. After being seen off from Yorihime, cherishing the last moment they held as they're erased to make things better for their past selves. Once back in the past, Solar collides with his past self, in his shadowy form, to destroy himself and the Route X timeline: where his past self receives medical attention and continues his respective timeline as normal. Upon the destruction of the timelines, whatever previous memories that were held had then vanished with no trace.