When he first started at RMI, Anssi was a subdued and soft-spoken boy, in part due to having only started learning English recently but also largely because he was (happily) overshadowed by his big brother/idol Ruben. Since then, he's developed into a still-soft-spoken but determined young adult with a strong sense of morality. He has a reputation of being a loyal friend, agreeable to go along with anything within his moral compass, and a genuinely sweet nature. However, he's very empathetic to other's problems, and has a tendency to fall down stress spirals.
In some ways, Anssi is obviously a Lundqvist: the high cheekbones, full mouth, blue eyes. In others, though, he is quite obviously not. His skin has a pinker tone and his hair is both a darker shade of blonde and much shorter than either of his siblings', currently shaved along the sides and back with the front section styled forwards or backwards depending on his mood. He hit a growth spurt in his mid-teens and is now on the tall side of average, but only slightly so. Having played as Chaser for Draco for most of his time at RMI, he has a lean muscle tone, though none of the bulk of his brother. His most distinguishing feature is a large port-wine birthmark that starts under his left ear and continue over part of his cheek, jaw, and neck; he was teased as a child and often tried to hide it, but since coming to RMI it has barely been pointed out by others, so he doesn't think of it any more. He is a casual dresser through since being named Prefect (now Head Boy), he's very committed to appearing put-together and like he has some kind of authority.
Mikael Anselm Ragnar Lundqvist is the only child of Leif Lundqvist and Saara Hämäläinen. As domestic partners, they lived together in Umeå for most of Anssi's childhood. Leif was widowed with two children, Dagny and Ruben, who were placed in foster care as a result of his alcoholism; it wasn't until Anssi was a toddler that Leif regained custody. Anssi's relationship with them was limited to holidays when the older Lundqvist children returned home from Durmstrang Institute. To the surprise of both his parents, the magic that had skipped over his Squib father landed in Anssi's genes instead. His first display of magic, Banishing feathers from a pillow and scattering them across the floor, occurred at the age of seven. This initiated a closer relationship with his magical half-siblings, especially his brother. He expected to join them at Durmstrang, but instead the Lundqvists moved to Houston, Texas when Anssi was 11 years old. Saara, being far more invested in academics than her tinkering partner, did some research and decided that RMI was the most logical option for her son's education.
School in general, playing Quidditch, sketching sceneries, spending time with friends on Pearl Street, certain aspects of the Prefect role (namely patrol duties and helping out younger students), Middle Eastern cuisine, the knowledge that he can turn into a goat (though when will his Animagus form ever come in handy?), Ruben's girlfriend Kaye, and occasionally Ruben too
Interpersonal conflict, physical violence, possibly physical contact in general (TBD), certain aspects of the Prefect role (namely having to break up horny teenagers in the not-so-secret passageways), Ruben most of the time
Anssi has no idea what he wants to do with his life. He'll probably apply to university, since it's free to attend in Sweden so why not, but beyond that? It's a big source of stress for him.