primehood is on the rise (wonderful fantastic please keep it coming), so for those that don't want to slog through all those headache-inducing crisis and crossover events to learn about superboy prime's history, here is an explanation of his character origin for any and all of your fan content characterization needs !!
it is so #%$@& prime time, indeed.
so! superboy prime has been around since the 80s, and he is, essentially, from our world. they call our world "earth prime" in the comics, hence the eventual "superboy prime" name.
in the beginning, he's just a normal comic nerd, a true superman fanboy, and he's named clark kent by coincidence by his adopted parents (yes, he does gets bullied for being named after a fictional character).
but, as it turns out, he actually is kryptonian! his powers set in when he's a teenager at a costume party, dressed as superman.
he gets about 30 seconds to be filled with childish whimsy upon discovering he can fly (just like his favorite hero!) and then he is whisked away by superman himself (holy shit superman is real!) to help with the first big "crisis" of DC history.
and um. well. then he fucking dies.
kinda dies, at least. many a confusing plot point occurs, and basically superboy prime's world is erased from existence while he, an old version of superman, and an alternate reality alexander luthor sacrifice themselves to help save the main DC continuity.
so prime "dies," in the 80s, a genuine hero! hurray!
it doesn't quite stick, though, because he ends up making a return during yet another crisis event about 20 years later, in 2006. surprise surprise, he wasn't dead, just trapped between realities for a few decades with nothing to do but watch over the world he'd sacrificed himself to save!
at some point in these many between-reality years, he ends up punching the walls of reality in (understandable) anger and frustration, causing a few... ripples, in the dc universe. mainly, what all the primehood shippers are talking about, ripples that are responsible for bringing jason todd back to life.
this is not on purpose, mind. it just so happens to be one of the many retcons that shattering reality's walls produced. no one (besides maybe prime, just by nature of him being a comic-reading, fourth wall-breaking character) knows that he is the one responsible for jason's resurrection.
on another note, hey, turns out losing your entire universe along with your family and your girlfriend laurie who you'd pined over for years and only just got with right before being killed and then getting trapped somewhere between realities without being able to age or mature for a few decades will uh. drive you a little crazy!
and hey, prime used to be a big comic lover, right? well all he did during these between-reality decades was watch as the main comic continuity got darker and grittier and sadder (which irl was because of comic laws changing and allowing for more violence and mature themes to be written into comics).
and this increasingly messed-up world is the one prime lost his own world to create, not to mention the one prime sacrificed himself to save. and so, well.
he may have become a psychotic, bratty, cynical villain about it?
(technically this descent into villainy isn't entirely on him, as he was being somewhat manipulated by the alexander guy that was trapped together with him all these years.)
regardless, with the help of alexander and old superman, he breaks out of the between-reality space, and wreaks a lot of general havoc on the world.
he also, notably, kills conner kent during this first soiree as a villain. something something, prime is the better superboy and conner doesn't deserve the "s," especially when he's a coward who quit being a hero when the world needed him.
(in conner's defense, he'd quit because he'd just discovered the whole half-luthor thing, and was brainwashed into hurting his friends in the process. also, he was actively walking out the door about to announce he was getting back out there anyway when prime attacked him)
prime's whole vibe during this and his subsequent villain arcs revolve around being very, very angry, mostly because he:
hates the current state of comics and wants them to go back to how they were in the silver age (the 50s-80s era of comics)
hates that everyone "made" him into a villain when he just wanted to be a hero
hates that his parents and girlfriend had been taken from him for nothing. he is particularly obsessed with the girlfriend part. laurie is brought up very frequently in his villain monologue-ing.
both alexander and old superman end up dying in the first comeback event, but the same cannot be said of superboy prime. cue a few years of prime killing people, getting locked away, and growing increasingly insane in prison until he escapes, which leads to him killing more people, getting locked away again, and growing somehow even more insane in prison until he escapes, again, and so on and so forth.
side note, one of his entrapments is done by the speedsters, and sparks funny beef between prime and specifically bart allen. prime is Not a fan of bart allen.
he even gets imprisoned back in a fake version of his world at some point, though his loved ones now fear him after reading about what he'd done to everyone in the comics.
this particular banishment marks the beginning of him being able to directly break the fourth wall, rather than just make metanarrative comments.
another recurring theme with prime is that he will always come back, or always get out, or always survive (rings a little similar to someone else i know...)
and then, finally, in 2020, he gets redeemed!
as he participates as a villain in yet another convoluted crossover event, he realizes how disillusioned he's become with his goal of getting his old life back. he's the only character that really knows just how many times the universe has been merged, destroyed, split, rebooted, etc. even if he got his loved ones back, would it last? would they ever truly be safe?
despite how crazy his sense of self has become as a result of all that aforementioned losing-his-entire-universe-and-being-locked-up-for-decades-and-returning-to-his-universe-only-to-discover-he-is-now-as-much-a-character-as-the-people-he-spent-years-killing-and-his-loved-ones-no-longer-love-him-related trauma, he recognizes he really didn't start out wanting to be a villain.
he is, at his core, a superman fan. and he has always loved what superman represents, wanted to be someone like superman himself, before everything about his life got so fucked up.
he also realizes that maybe it's ok for the characters you love to change! maybe growing and learning and being a fallible human is representation we should actually want in our comics (cough COUGH). diana, in the midst of prime's redemption arc, puts it best:
and so, he decides he's had enough. he's gonna finally start acting like the hero he was so passionate about reading all those years ago. in a big climactic moment, he chooses to sacrifice himself, and his dream of ever returning home, to save the multiverse. again.
... but wait....
lol you thought he was gone for real? nah. turns out, he's somehow back in his world again, except his loved ones don't hate him anymore! also, his powers came back with him!
after telling us to go touch grass, he gets his happy "to be continued..?" and disappears from dc stories for 5 years.
but, of course, because he is superboy prime and he always comes back, we see him again in 2025 for yet another giant crossover event (some things never change).
apparently, that nice perfect world he was in was not actually real, but instead a pocket universe used to hide him from the big bad evil guy darkseid.
prime is already aware of this fact, and also pretty accepting of it. i guess he finally self-actualized over the five years he got to spend living in his paradise dream world. he's definitely a much less serious and much more joke-cracking kind of guy now.
so! he leaves it all behind to help superman, and he is now officially back in the main continuity as the superfam's newest nobody-even-invited-you member!
(also, apparently he’s taking over The Superman Mantle after this event concludes? so that’s something to look out for.)
do the other characters trust him? no, not really. has he done very bad things that he'll probably never be able to scrub from his past? yeah, pretty much. was he once angry with the world for what it did to him and did that anger eventually transform him into something that might just be capable of bringing about positive change? you betcha.
is that all strangely reminiscent of another black-sheep-of-the-family dc character with incidental but literally existential ties to his past? yup. sure is.
congrats! you now know what's up with superboy prime. go off and put more primehood into the universe, it's what jason would absolutely not want (but prime would probably find very, very funny).