Okay so I have a theory on what Kaydens backstory might be.I think I might be over analysing and nitpicking, but you guys can be the judge.
So my theory is that Kayden may come from some sort of military/government family.
Point one: His meeting with Jiwoo.
When he first finds out Jiwoo doesn't know what an Awakener is, his reaction is "oh right there are some kids like you". This could mean Kayden already had knowledge of the awakener world. There are two scenarios where this is plausible; he was born into an awakener family, but the fact that not even one organisation knows what his last name is goes against this. Another scenario is that he could be from a military/government family, it's been stated that the government knows that awakeners exist. Upon getting his powers he could have just been told by his family about the awakener world.
Second point: Kayden seems to know a lot of details about many organisations, along with being very knowledgeable about awakener world politics.
At first this can just be pushed off as Kayden learning details about people he wants to fight. One thing that's off here is the fact that he seems to also know about the children of the organisations. Case and point he already seems to know about Duke and about the talents of other groups. He could have started researching for Jiwoo, but that doesn't seem to be in line with Kayden's way of teaching. He also already knew of Jiyoung's talent even though she managed to hide it from most of the awakened society. Another thing to consider is the fact that he can predict the behaviour of the other top ten, and knows their personality well. He knows that Schneider would most likely kill Duke if he lost, and he was right he was going to kill Duke. From the interaction they have with each other, it's clear that this is the first time Schneider has met Kayden face to face. Yet Kayden already seems to know the nuances of his personality. He was right about Supri wanting to take their side over Andrei's. Even when the Korean awakeners where on the fence on what Astras would do to them, Kayden already knew for a fact that Astra would move with a 100% certainty. He also knew the location of those three top 10 that attacked him. There is no mention of a gathering of those three by anyone in Korea, despite the fact that would be a huge deal since it was either happening near or in Korea. Yet they clearly know of Kayden's entry, which could mean that the other 3 were meeting in secret. Yet Kayden ended up finding them.
Point 3: Somehow a young Kayden didn't pop up on any organisation's radar.
Somehow a child/teenage Kayden didn't get forced to join any organisation. From Sucheons grandfather we can see that teens with potential could be forced into joining organisations. They could also be forced to join criminal organisations. Kayden made his debut fighting people, and he was at a level that he couldn't be forced into joining any group. Kayden from the get go clearly decides he doesn't want to be in an organisation despite it's benefits. If he came from a military/government family it would make sense that they would have; the power to hide him, knowledge of the operations of the awakener world, plus a safe space for him to train while hidden.
Point 4: His mannerisms.
Whenever we see glimpses of Kayden walking he always holds an upright straight posture, this can also be seen in the way he sits;he sits upright with his legs crossed. Another thing to note is that unless Kayden is fighting, his personality is more on the cordial side. When Kayden first meets Jiwoo he's annoyed but he doesn't just abandon Jiwoo, many of the powerful awakners shown wouldn't even entertain the cat catching shenanigans in the first few chapters. He also doesn't really seem to find the act of teasing Iseul for her crush amusing, his reactions show that he thinks such things are just unnecessary or maybe rude. Kayden also in a couple chapters, not only in Ian's gives criticism on manners. Kayden doesn't slouch unless he's trying to aggravate or annoy someone and his personality becomes more volatile when aggravated. Kayden also shows formal manners when meeting Jiwoo's mom, he doesn't necessarily have to introduce himself in such a manner; it is his own choice to present himself in such a manner towards his mom. From Kartiens reaction we know that Kayden didn't really need to present himself in such a way. The other top ten save for Supri and Veremonte wouldn't have even bothered to give a shrivel of politeness, and even in the case of Supri and Veremonte they wouldn't have been as polite. If Kayden is from a military/government family it would make sense that manners would be something that he was forced to learn.
As for why his family would let him do the things he does? I have no clue. Maybe he's a runaway, maybe he's an illegitimate child. Maybe his Family hid him away and didn't let the public know of his existence. Since powers show up when young, maybe his showed up early and his family decided to hide him.Maybe once he was discovered to have powers his family trained him to be a weapon. This theory makes a full on Rabbit hole of other theories.
I think I'm just overanalyzing things. Again this is just a theory I randomly thought of no one needs to take it seriously. Even the evidence is kind of happenstance. This is just an idea I thought was fun. If anyone has any theories of what Kaydens life may have been I would love to hear it.











