Narrator's pov:
At night time at location of destroy where the idols about to sing live on stage, the rubble was over the place, buildings all screw up and broken, amongs the damage stage and all there was a lifeless body with a hole on its chest on a puddle of blood which later began to rain with soulless eyes, at the same time a figure land on the stage which something separate a female body with red hair and dark red, now the thing that came out of red hair girl was an alien which reveal its real form.
Red hair girl: so which earth is this time? Its identical than mine earth, and this stage looks destroy or swarm by noises- she ask looking around the place-
Alien: according to this radar, this timeline is version where you die and alot of crap happen involve with tsubasa and rest of those two, but it also tells me there's more like you who uses relics Kanade.
Kanade amo, tsubasa's old companion.
Kanade: really now? Well hopefully get to see her growth or at least made friends.
Alien: hmm, friends huh? You remind me of that lab rat i possess once for my evolution stages- laughs then sighs remember times he mock them and spend time before doing his plan-
Kanade: 7-7 in what way evolt?- she raises an eyebrown looking at him-
Evolt
Evolt: uhhh...huh? Well well well what we got here..~ - sighs approaching the dead body on the puddle-
????:....
Kanade: hm? Who is that? I never remember someone here or any timeline- approach and crouches to poke his face-
Evolt: - checks his wallet and pulls an ID pass on the stage- his name is...Y/n L/n, a student from lydian private music school, age 18 and; OHHHH a fighter and a singer? Interesting and...i sense hazard level on his body right now.
Kanade: what? What you mean Evolt?- she ask while poking his face more-
Evolt: i mean that this hazard level is keeping him alive, must have activated upon death and its have not much time before he is dead dead like dead as f*ck.
Kanade: and how will he recover before its too late.
Evolt: i may merge with him preventing him to stay dead, and heal him over time.
Kanade: stop the cap, you just wanna possessed him like old times sake and last time you did that you grope my boobs! You pervert
Evolt: hey i did it for experiments and-
Suddenly hears footsteps coming in few minutes.
Evolt: tch there coming, you better hide kanade and keep an eye on him, this experiement should be fun~ and of course i will provide him support....aaaaand may mess around with-
Kanade: don't!
Evolt: ugh fine, ciao~
As evolt merge with Y/n's dead body he manage to peak into his memories to learn about him and heal up the hole from his chest a group of agent arrive while kanade hide from the pile, one of agents analyze Y/n and the boy was breathing but weaker that one of use a communicator to contact to base
Bravo1: HQ this is bravo 1, the boy is breathing i repeat the boy is breathing over.
HQ: confirm bravo1 bring him back home to nurse him over.
Bravo1: Roger that, bravo1 out - ends the comunicator- you got your orders, bring him back ASAP.
- timeskip at S.O.N.G base-
At the command center, a male figure was on the chair seeing status of supporters about Y/n analize and was normal but still a red alter on his systems kept stable yet dangerous level rising bit by bit., the male figure cross his arms looking at the those condicions of his.
Genjuro aka giga chad xd
Genjuro: hmm those are same thing that we analize him before he could be part of group, but no result, have we tried anything new to this condicion.
Random guy: we tried analize it but nothing, no options Yet it heal him like nothing, plus his status just kept getting stronger but in not dangerous way for him.
Genjuro: hmmm
????: have you tried test his hazard level Genjuro-san?
Genjuro: - he turn around and saw the figure- hmm hazard level? Your speaking as if something to do with that "Box" kiryu sento.
Kiryu sento, kamen rider build.
Sento: yeah, though the box now resonates to him as if something or someone return and decided to plant it inside of him, his hazard level may be worth testing him and if im correct with this condicion and laws, we may discover a possible kamen rider.
Genjuro: . . . . why now?- looks at the screen of Y/n in coma -
Genjuro: .... Sento, i will give you permission to check on him and when were certain,may test him alright?
Sento: understood, now then....let it begin the project, after all we need help what we can anyways.
Prologue end
Next time: the experiment and the singer