Long black hair and maroon eyes. Strongest Demon Slayer to ever exist. He is the inventor of Breathing Styles, being the one who created the first ever Breathing Style. Emotionless, calm, reserved, intelligent. He can't feel love. But if he feels, he will never let go of his love. 

Calm and reserved

Although Senku has a strong sense of justice, he often bends the rules, and manipulates others to get what he wants.He often acts as if he builds inventions and uses people for his own interest, while actually creating for the betterment of others.Senku has a very logical mind, believing that there is nothing science cannot explain, even if it takes a long time to properly understand any one concept through science.Senku seems apathetic to the prospect of romance. He has red eyes.

He is very arrogant, protective, calm, manipulative, strong, possessive, jealous, obsessive 
He likes to tease a lot 
He is a good fighter, very agile and intelligent 
He is independent, gets angry very hard 
He's very sarcastic
He is not afraid of anything 
When he loves, he loves with his body, but also with his soul 
He is 1.70, black hair, black eyes, big red lips.
He likes to seduce. 