I don't own Ben 10 or JL, this is just fanfic please don't sue. Thanks :)
Being an intergalactic superhero is not an easy thing, most of the time you're either off-world fighting warlords or settling inter-galactic, especially when the most powerful weapon that is in your hands not only getting more powerful by having more of its features unlocked but is also being integrated into your genes. After dealing with a diplomatic fight between the Incursean and the Tetramand, he then flew back to earth as it has been 5 years since he's been doing his inter-galactic peacekeeping duties and thought it time to go back for a visit.
Having festivities in his house when he got home was one of the happiest moments in his life until Vilgax destroyed the entire universe with the Anihilaarg, unable to accept this kind of end he tried to turn to Alien X to rescue the universe for the umpteenth time, but was stopped by the council of Celestialsapien, in which he was given a choice, the council will help return the universe back to the moment where it got destroyed and prevent it from happening, but he will have to leave this universe and never come back or stay in this void of a dimension and be the one in charge of it as a Celestialsapient forever.