Speculating on the Personality Quirks of the Borderlands 4 Vaulthunters.
Starting with the Black Lady. I think she's too smart for her own good. So everyone seems to agree she's ex-Maliwan. Here's the thing about Maliwan. You're either completely out of your mind to want to work for them. Or you're incredibly sane and don't want to work for them. We have 2 confirmed cases of Ex-Maliwan Employees. Zane and Naoko. Zane was in a black ops unit and dipped and probably stole Maliwan Tech. Very sane thing to do. Naoko was Kategawas sibling and then dipped when he tried to kill her to prevent her from absorbing the company. Now it's possible Naoko is still at Maliwan and is still hiding out until the CEO finally dies but we see Kategawa SR is still the CEO of Maliwan come New Tales of the Borderlands which happens 3 or 4 years after the events of Borderlands 3. As the book Worlds of Borderlands was written a year and 6 months after the events of Borderlands 3. But given Naokos intelligence it would make sense that she is still hiding until the CEO croaks so she can step right in and become CEO. Wh8ch would be the very sane thing to do. Another thing about Maliwan is that it absolutely sucks to work there if you're not a the top of the food chain. Kategawa himself despite his position had a barcode at the back of his neck because that's all Maliwan sees it's employees as. As property. If the black lady was ex-maliwan she more than likely left for very logical reasons. The job fucking SUCKS. It wouldn't surprise me if she was involved in some cutting in research but she got no credit for any of it all so she stole what she could to do better for herself. She might be the most normal out of the whole group but is down on some tough times having left one of the worst places to work for ever. But she stole a Maliwan AI that she helped create so she's gonna make a ton of money off it hunting down Vaults. It all works out. The reason I think this is because she wears surprising low amount of actual armor or suits other than her legs which would make sense if she had some type of tech that allows her to have to pilot something that's digistructed from seemingly thin air. In addition to having a jetpack and a grapplehook with pants that connect to something behind her back. Which she more than likely logically stole from Maliwan.
Now enter the Muscly Viking Dude. There's no context on this guy. Borderlands always has 2 characters that just show up with no lore context at all. I'm thinking this guys one of them. So I think what they're going for here is not to judge a book by its cover. Now had this been BL1/BL2 era this guy would just be the Salvador/Brick of the group whose just a complete combatative muscle bound meathead. However come Presequel and Borderlands 3 and Wonderlands this trope kinda is no longer a thing at least for playable characters. So I'm thinking that this guy is the running underlying joke of someone's actually super into and hyper fixated on something. Mordecai has his pet. Gaige has her deathtrap. FL4K had just an overall thing going on with animals....and this guy I think really likes he grenades. This guy is into Vaultlanders. For some reason this guy looks like a dude whose crippling into Vaultlanders and or other forms of geekdom in our world similar to Warhammer 40k including Bunkers and Badasses. The joke has to somehow live in BL4...and I think this guy is what's gonna keep it alive. I think it works because he's completely not what you'd expect him to be into so him being the fucking Henry Cavill of Vaulthunters is a bit endearing because he should be likeable as well and that's not his entire personality but rather just a quirk about him, which I think is what ultimately influences the way he fights we see him throw these fucking Viking Style Grenades that he prpbably made himself cause he's super into Bunkers and Badasses.
Then there's the Siren. I'm not gonna sugarcoat this. She's probably THE freakiest vaulthunter were ever gonna play. Yes I do mean this in a sexual way. I believe she gets her jollies off dominating people. There's a reason for this. So alot of people seem to agree she's gotten Steeles powers now typically whenever we've seen a Siren inherit or in Tyreens case share someone else's powers....they're actually very similar to each other. Tannis and Angel shared a bit of similarity to each other. Maya and Ava as well. And Troy and Tyreen are literally twins. So if someone inherited Steeles powers...she's probably like Steele. So what was Steele like? There's a few things we know about her thanks to outside sources from her appearance...her relationship with General Knoxx SUCKED. She would never shut up and she was a yapper. But Steele also hated Knoxx so she probably did this just to fuck with him knowing it pissed him off. What Steele actually liked...was having an iron fist. And she disliked disobedience. She was an absolute control freak....and the whole point in having an iron fist is to dominate your will over others....Her last quotes which were recovered from the game actually say that she expressedly wanted to imprison the Vaulthunters to keep herself and Tannis company....now here's the thing....If she liked having such an Iron fist to the point where it felt sexual....this is now infinitely more disturbing yet humorous because shes so enamored with herself in such a way she literally tefers to herself in the 3rd person.....so if things turned out in her favor and wanted to have authority over like an iron fist....to the point where she felt sexual satisfaction from that...she woulf have kept you imprisoned and gotten her rocks off torturing you the entire time. Another thing about Steele is she more than likely inherited her powers from Queen Dido. Queen Dido being a literal grandma with boney fingers, became sexually attracted to an 18-20 year old Typhon Deleon who was held captive by her. And grabbed his ass cheeks as they were dancing when Typhon ripped his way put of it and kissed him. She was a gilf FREAK who ruled Athenas for quite a long time. So yeah the freaky pipeline going on there might just be a thing from Dido to Steele to now the Asian Baddy witha Choker. And if it is and the Asian Baddy with a Choker inherited Steeles powers...she's probably a freak and a complete bitch, which alot of people are gonna find hot as hell. Like into seeing dudes get brutally dominated. And or sepcifically likes doing the dominating. The Freaky Moxxi Siren. She even has the same color as her for her tattoos. Witch could play inter her powers...if she can construct murderous....torturous toys she can use on people....out of seemingly the fabric of reality. So that being said she's probably in or was in the assassination business and only gets out of it because of the call all Sirens seem to get at some point that draws them towards one another. Another interesting thing that supports this is each Siren from Borderlands 1 through 3 was presented as an opposite of the other. Lilith was a geek who was made fun of and liked to feel pretty so as to be liked. Maya was completely revered as a goddess and hated that and didn't have social interactions growing up. Amara is a freedom fighter and a crime fighter who does it for fame, fortune, protecting the innocent and a means to cure her boredom. This Chick probably breaks the law and is never usually bored because she's constantly getting her jollies off torturing the masses in some way. So this woman
And lastly we have what everyone is dubbing the most ordinary dude. I'm gonna go off a limb and say he's gay. I don't know just a hunch. So in regards to his personality he's probably going to be the most openly so. I think he might be into designer/brand clothing and wants to get into and start a New-U business. Like one designed to look stylish while using tech. I'm sure him and Zane are gonna get along quite nicely. He's the only Vaulthunter actually wearing brand clothing. And it does look oddly like something Octavio would wear in New Tales from the Borderlands. I need to double check but I believe Octavio does start his own brand of apparel in an alternate ending. But in regards to his quirk. He's super stylish. Yeah like probably to a fault. The way he fights is quite flashy and stylish and doesn't hinder his outfit which is still visible. And hes probably openly mega in people's faces if they lack style. Or their fit sucks. Quite literal rags to riches.
The Asian Lady and the black lady are probably the 2 Vaulthunters with pre-established context from the existing lore. I want to assume that their personalities are in a great deal formed around that. While the 2 dudes are completely unknown and I'm kind of just aimlessly assuming in large detail on what they'll act like in the game. Just based off how they look.