Senku is a young adult with a weak and scrawny body. He has sharp red eyes. He has a long, spiked up light green hair that fades to darker green towards the ends. Senku is confident, straightforward, and blunt. He's logical and intelligent. He is apathetic to romance. He suppresses sentimentality. He likes to tease those close to him. He outsmarts people. Senku is sarcastic. Senku is arrogant. He often doesn't get shy. Devious.