Basically, Onyx and Loki, out for revenge now that Lightning has Mjolnir, run into Necrozma, who managed to survive its fight with Mebius. Sensing light, Necrozma tries to possess Onyx, only for Loki's power to possess Necrozma instead, so he and Onyx control the fusion.
With this power, Necronyx travels into Ultra Space and sucks a bunch of Ultras, including Lightning, into it. The Ultras fight some Ultra Beasts and eventually Necronyx, who soon transforms into Ultra Necrozma, which Loki may even further upgrade with his own power.
So all the heroes beat him and go home, HOWEVER, Zero gets lost somehow, or maybe his bracelet just gets damaged. He ends up on Earth, and is unable to leave. That's how the Beyond oneshot begins.
All of my characters come from after Ultraman Mebius Returns: Burning Heart, Freezing Heart.
- Ultraman Lightning
- Ultraman Onyx
- Ultraman Mebius
- Ultraman Hikari
- Ultraman Zero
- Ultraman Geed
Beast comes from after his series. Blank and Prince come from after Prince's series, but presumably before Prince joins the Parody Garrison.
Team Legacy presumably comes from after Ultraman Lightning, Legacy, Blizzard: Baron of Darkness and the ROTDC Gaiden. Nerf and Average are likely from before or after Parody Hero Taisen, depending on whether Prince has a role in the Spin-Off.
Blizzard comes from after Blizzard Side Story: Planet of Ice, so he has his Evolved Types.
These characters all come from after the Rise of the Dark Cross Gaiden.
Mao Wu Kong
These characters all come from after Prisman's series, and somewhere during Falcon's.
Deino comes from the middle of his series.
- Ultraman Notus
- Ultraman Gaia
- Ultraman Agul
- Ultraman Terra Firma