His favorite subject is Math while his least favorite is Japanese.
His hobbies/specialty are provocation, mischief, and harassment.
His favorite food is his own cooking.
Karma is the first student that managed to inflict damage on Korosensei.
He wants to become an evil bureaucrat in the future.
His first name only appears in kanji (業) during his formal introduction. The other students, and eventually also Korosensei, refer to him with the katakana (カルマ) version of his name.
He was called "Chuunihan (中二半)" during Class 3-E training using code names. This was given to him by Hazama, and refers to how he's "half" of a Chuunibiyou due to him being so lazy. [1]
Karma is one of the few people in the entire manga who is referred to by his first name.
In the popularity poll of Volume 12, he was the highest ranked character, achieving 1st place.
In the tankobon extras, his statistics were listed as:
Physical strength: 4
Mobility: 4
Close-range assassination: 4.5
Long-range assassination: 4.5
Academic ability: 5
Characteristic skill: 5 (fighting)
As of Chapter 123, Karma is the top ranking student of Kunugigaoka, placing first with a perfect score of 500.
His previous rankings in order follow: 4th, 13th, and 2nd.
He shares both his Japanese and English voice actors with Accelerator from the Toaru Series.