Liam Payne
He's "The Responsible One." He's the third youngest in the band, but they call him Daddy Direction because he is forced to act like the voice of reason. Because of this, he's often characterized as being really smart/intellectual in fics, and that's just not true. Check out his twitter for some misspelling gems and general adorableness. He is the most active band member on twitter. He is almost no one's favorite, but he should be more popular. He's also the best singer in the band.
Performance uniform: plaid shirts
Niall Horan
"The Cute One." He's the baby of the band, even though is is the second youngest. He's from Mullingar, Ireland, and he is VERY proud of being Irish. It is his defining characteristic. He also loves food and eats a ton. He's basically the fandom bicycle. He looks really innocent, so a lot of people write him being everyone's bottom. He has a great friendship with the band's drummer, Josh Devine. He has been playing guitar since he was 11, and he has started playing with the band during live shows. Lately he's also been dressing like a bro, which is basically the most hilarious thing ever.
Performance uniform: Polos and sweaters
Louis Tomlinson
"The Mischievous One" according to himself. He is the oldest person in the band, but he often acts like the youngest. He has a very loud personality and likes to do things like bite his bandmates' necks during interviews. He loves Grease and football, in that order. He discovered his love for performing after being cast as Danny Zuko in his school's performance of Greece. His nickname is "Boo Bear" because apparently his mom called him that when he was SUPER young, and some interviewer asked about it and he got super embarrassed. I think he gets embarrassed easily so his loudness is a form of self-protection.
Performance uniform: Stripes and suspenders
Harry Styles
"The Sexual One." He's the youngest in the band, but he is fond of dirty jokes and he makes them in interviews. He speaks really slowly and is the tallest one in the band, but he slouches all the time. He has the second-best voice after Liam, and he gets a lot of solos. He gets nervous during his solos so the rest of the band fucks with him while he sings by messing up his hair and touching his ass. A lot of people think he's pansexual, because he definitely likes girls, but he also never uses gendered pronouns when speaking about what he's looking for in a partner, and he's been photographed at a gay bar wearing a "Love is Equal" shirt. He is my favorite because he is a really endearing person who tells girls off at signings for saying the word nigger and he is also a little shit. He's really subby.
Performance uniform: Blazers, collared shirts, and bow ties
Zayn Malik
"The Pretty One." He's the second oldest in the band. He's half Pakistani, have British/English, and he is characterized as being the mysterious~ one because he's the quietest in interviews and has a good poutface. He is a self-described comic book nerd and he likes to draw cartoons of the other guys in the band. He used to be super shy and Simon had to make him go to the dance portion of the X Factor auditions. Now he is a lot more self-confident.
Performance uniform: Varsity jackets, boots, sweaters
OK I ran out of time so I'll do a proper picspam and also like a 4 part primer later.