Hi >:D I'm not the one in charge of Doc for the AU, but here's what we had for him so far: he's 28 (so 22 when he joined the PM), previously worked for the government along Pianoman, Lippmann and Iceman, although he had his own subordinates and lab, where he'd take do his usual med research but also research on venom... There's snakes in his lab, a lot of snakes, he loves snakes, he's obsessed with snakes. In fact so obsessed he lost his right arm after getting bitten and having to amputate it (fun). Doesn't wear a prosthetic regardless and he still hand-feeds them like a champ. Did a lot of unethical experiments on humans before joining the gov but that's not really surprising

OH I have an answer! With some... Degree of explanation if you're interested

Pianoman is canonly 25 so that's that

Albatross is 18-19 in my eyes, and look don't get me wrong the teens in BSD do the absolute craziest shit and he's profoundly immature but a little voice inside my head associates punk teens with late high school/graduation years, where teens tend to party and go out the most yada yada. Also it's the "officially has a reason to fuck off from home" time (but in my mind he's homeschooled, fucked off way before even being an adult)

For Lippman, easily 21-22, first because otherwise the continuity I established for my Pianolipp hcs wouldn't work, and because he has to be that young man that appeals to younger people/teens but also has the maturity to speak the way that he does, had the time to Kickstart a successful career as an actor in Japan, also had to be an adult to travel around if he did so alone (since he's American)

Iceman would be 23-24, same as Oda, he strikes me as old man kinda LOL but is somehow younger than Piano Man canonly so!

Doc... trick question tbh because clearly his illness doesn't do him any favors but I'd place him at above 22 minimum for the sole and unique reason that a doctorate requires four years minimum and can go up to eight years at most to acquire... in America, where he got it from. Yes I did my maths unlike Asagiri, shame on you Asagiri

SO DO I SO DO I!!! There are so many, and most come from a roleplay I have with a friend with established a whole timeline of their lives SO. But here's a (short) list of the most important HCs I have for them :
- Pianoman (then 21) met Lippmann (then 19) for the first time at an airport, reason being Lippmann sort of fled America to Kickstart his career in Japan (and far away from his family), and Pianoman pretty much forged all the papers required such as a visa, which would normally take months and months of procedures ANYWAYS. They meet and not much happens but they do exchange numbers, in case Lippmann needed help for whatever reason (Pianoman didn't let him know he was from the Mafia at that point)... Without sharing too many details Lippmann did end up joining the Port Mafia through him for his talents and influence
- Second HC, Pianoman being a huge workaholic--let's be real here for a sec--so Lippmann would drop off food in his office, make sure he stays hydrated yada yada. Even when they weren't dating yet, Lippmann was just like pls don't die on me
- Third HC is that, as you can see I love drawing them with rings. Thing is they never got officially engaged, or even told anyone (maybe just the Flags because they were painfully obvious abt it)--they died before they could marry. Which is sad, but such is life!

I HAVE MORE BUT THIS IS ALREADY A LOT THANK YOU FOR ASKING AND READING THIS FAR AAAAA

Oh lawd, small essay incoming 😭
So, I don't know why, but whenever I hop into a new franchise I get attached to a couple charas and then... No matter what I will always tend to gravitate towards the missing/dead characters for no particular reason. In Genshin it was Nameless bard, in Enstars it was Kaname, in HSR it was Dan Feng before he was even revealed to be playable. The thing in common between these charas is that they helped shape another chara (alive) that I like. So for BSD, it's like, Chuuya & the Flags. Something about secondary charas that we don't know much about is just magical to me, because then I have a lot more ground to make up and imagine stuff with them, since little is canonly known!

As for the Flags specially, the mutualism and the fact that they are the youngest helps ig. Anyways this is VERY ironic because I dislike Mcd and Stormbringer broke me of course regarding that of course but... Yeah, brain weird sometimes ig?

I honestly wouldn't be able to explain exactly why Kaname, but I do tend to have a pattern for which characters I end up obsessing over and those I don't.

As soon as I read Obbligato I fell in love, as soon as I knew HiMERU wasn't really HiMERU, I wanted--YEARNED to know more and oh boy I didn't regret the tears at all!
Kaname is quite literally a reflection of HiMERU, the persona he's created. While the explanation given is that Reimei SP students are told to make a persona/have a stage name, I do believe the creation of HiMERU stems from much deeper than that

Kaname is, simply put, extremely flawed: he pretends to be smart but isn't, is short-tempered, loud, childish and rude, everything that HiMERU isn't. HiMERU is merely a mask to veil all of his insecurities behind, to pretend to be someone he's not--just like his brother is doing today.

So on the psychological side of things, I love that baby a lot. But I seem to have a weakness for what I like to 'bitchbabies' or well, characters that either pretend to be smartasses, or actually are smartasses but quite rude about it. In general, flawed characters that yearn to do better/overcome trauma are also charas I'm drawn to for the heart-breaking angsty aspect they can bring to a story!