Sumiaki Iwashimizu is a character from the anime series All Out!!, which focuses on the sport of rugby. Sumiaki, often called 'Sumi,' is a tall and gentle second-year student at Kanagawa High School. Despite his imposing stature, he is soft-spoken and struggles with self-confidence. Initially hesitant about playing rugby due to a past incident, he is encouraged by his teammates to embrace his potential. Throughout the series, Sumiaki grows both as a player and as an individual, learning to overcome his fears and support his team as a dependable lock forward.