SessInu is a yaoi pairing from the anime Inuyasha, which pairs Sesshomaru with his brother Inuyasha. Yaoi is like boyxboy anime.
"SessInu" is commonly used as a shorthand for Sesshomaru and Inuyasha, two characters from the anime series "Inuyasha." Sesshomaru is Inuyasha's older half-brother, known for his stoic demeanor and powerful abilities, while Inuyasha is the main protagonist with a half-demon heritage and a desire to become a full demon. The bond between the two brothers is a central theme in the series.