|“||It's too bad that you're fighting against your opponent's strong point...||”|
He is currently ranked #3 out of the original 300 forwards chosen to be apart of the Blue Lock Project and is currently starting as a defensive midfielder for the Blue Lock Eleven against the Japan U-20.
Karasu is a tall and lean young man with dark blue hair with a spiky purple top and has a mole under his right eye. His appearance is supposed to somewhat resemble a crow.
At Blue Lock, Karasu wears the standard issued body suit (black with gray stripes) and tracksuit. During Second Selection, he wore Team Red's #69 jersey and wore Team B's #69 white jersey during the Third Selection. Only once the Japan National Representative match begins does he don an official blue Blue Lock player uniform with the jersey #6.
Karasu tends to look down on people he finds 'mediocre'. He is wary of his surroundings and is able to control and produce chemical reactions with those around him. He is intelligent, however has a sharp tongue and never misses a chance to insult someone, whether friend or foe. He has his own rules that he forces upon others to make matches go as planned. He dislikes it when anything goes wrong, even if it doesn't make a big difference so it looks like to others like he is always complaining.
During the U-20 match, Karasu showed his leadership ability on defense, often communicating with the other defensive players to strategize against the quickly incoming U-20 players. He commands players like Yo Hiori and Kenyu Yukimiya in terms of attacking and defending, even if the players are aware of what to do. He also is willing to take every advantage when he asked the referee to card Ryusei Shidou for happening to kick Rin Itoshi in the face.
- Midfield General: A central midfield player who absolutely controls the midfield area, directing team play and breaking up the opponent's attacks. They are known for having the biggest influence on their team's overall performances, driving them forward to attack, putting sustained pressure on the opposition and leading by example when the team is defending.
Sharp Analytical Ability: Karasu is renowned for his tactical shrewdness, having a reputation for targeting an enemy team's weakest link/player and focusing his plays against them (as stated by Hiori). His analytical ability was at such a level (along with his ball-keeping), that Ego made the decision to position him as the defensive midfielder of the Blue Lock 11, to act as the beating heart of the team, transitioning from defense to offense. Karasu has demonstrated an incredible grasp of tactics, being able to breakdown the U-20's defensive set up and the likely steps they will take to prevent an attack. After doing so, he was able to organise an attack with both Otoya and Chigiri to break through their defence, leading to Blue Lock's second goal. Karasu has also shown good awareness, knowing when to stall in the defence (against Sae), giving his team time to organise, as well as when to join the offensive line, providing an extra option.
Expert Ball Control: Karasu has the best ball-keeping sense in Blue Lock, due to his spatial and tactical awareness and his unique ability to control space with his hands. By gauging the distance between himself and his opponent, Karasu uses his body (and more specifically his arms) to block them off from the ball, controlling the space and enabling him to either steal the ball from them or dribble past.
- Feints: Karasu, in conjunction with his ability to control space with his hands, uses devastating feints to his advantage. He typically feigns carelessness with the ball, to draw his opponent in, before shifting the ball away, as well as shifting the opponent's center of gravity with his hands. Through his expert use of feints and spatial control, Karasu was able to dribble past at least 2 players at once (in Isagi and Shidou), as well as maintain possession when pressured by 3 players at once (Isagi, Shidou and Nanase).
- (To Isagi) It's too bad that you're fighting against your opponent's strong point... If you aim for their weak points, your chances of winning will greatly increase. Yoichi Isagi you're the weak point of this team. 
- (To Isagi) If you're surrounded with all your special buddies, you could be able to synergize, by your lonesome, your coordination is nothing but mediocre. I guess watching all those VTR videos had results after all. I'm gonna crush you and your team. 
- (To Isagi) I will beat you down until you overdose, idiot. 
- (To Isagi) See, I told you. On your own, you're just ordinary. You're dragging your entire team down with you, Isagi Yoichi. 
- (To Rin) Using the same momentum to pull me away from you and to shoot for the goal real smart, Mr. Abnormal (Rin). And what's more, since Mr. Ordinary (Isagi) there decided to awaken... You guys there have become a completely different team of your own. 
- He is scared of the water.
- He was in the same youth team as Yo Hiori.
- He remembers his first crush pretty well: he says he had been eight years old, and her name was Marisa. Karasu also notes he feels like he's mediocre because of that, she was the cutest in class.
- He prefers the bamboo shoot snack over mushroom snack.
- He was in the same team with Kenyu Yukimiya and Eita Otoya in the Second Selection.
- His nickname is Assassin.
- His hometown is in Kyoto.
- His least favorite school subject is swimming.
- His favorite song is Grapevine - Fly.
- His favorite drink is Kelp Tea.
- His favorite animal is the hawk.
- When taking a bath, he washes his hair first because he used a lot of hair wax.
- His favorite TV show is Documental (“HITOSHI MATSUMOTO presents ドキュメンタル”) (a comedy show in which ten comics try to make each other laugh)
- His favorite manga is GANTZ (Osaka arc)
- He won't tell when he cried last time