Quinton's...not very old, is he? Not as old as he looks at least. It would explain his coloring book and juice box preferences, but the song choice here confirms it. Along with Abby and Bianca's reactions here (kind of like older sisters watching their baby brother do something adorable). It would also explain his lack of concern for others beyond good ol' sociopathy.
Plus the twins' words on ch 5 p 24; "I don't think he really understands...They had him down there for a really long time." So a really long time could be since birth, or perhaps Quinton really is far older than all of them, but his mind and body were put in stasis at a very young age to preserve his health during containment.
And also the nature of his powers--Somehow I doubt he got them really recently like Simon and Abby/Bianca, which would only leave the possibility that he was born with them (which upholds my above theory). Since the only way you could be born with abilities is through some pretty interesting family traits, I'm thinking that's what occurred with him. On ch 5 p 20 when asked to describe Nilus, he said "Like me...But not the same." So since Nilus **SPOILER ALERT!!** is a demigod child of Tia, an atlantean goddess of the sea (I think)**SPOILER OVER!!** (from book 4 extras) I think Quinton was created in much the same way. Especially his eyes, and so far the only characters we've seen with different eyes were those that weren't entirely human or somehow related to something that was different.
My Sincere Apologies
I do not know what possessed me to pass on this comic when I have stumbled across in the past. I just actually read it today and it is already in my list of favorites. I look forward to seeing more.
@ anonymoose: Honestly, I have no idea how old Quinton is. He has age control powers (how he changes both his own and others ages) so he could be anywhere between as old as The Gentleman, or only a teenager. And, honestly, the level of experiences he has had could be VASTLY different from how long he's lived.
The "They had him down there for a really long time" comment on ch 5 p 24 could mean anything. I, personally, belive that the twins are preteens, meaning that their "really long time" could be anywhere above a year, with increased likelyhood of five years.
Honestly, though, I think that Quinton was drugged to sleep for most of his time in the half-stated incarceration. Only coming to conciousness to be drugged to restore someone's youth, before being drugged back to sleep. If this is the case, then the constant drugging may have had a possibly permanent side effect on his brain chemestry. This is what I suspect is the reason for his lack of concern for others.