Quick Answers
What is the relationship between Sae Itoshi and Rin Itoshi?
How did Sae Itoshi influence Rin Itoshi's interest in football?
What was the promise made between Sae and Rin Itoshi?
How did Sae Itoshi end up playing for the inferiors of Real Madrid?
How did Sae and Rin Itoshi's relationship change after they got separated?
Family[]
Rin Itoshi[]
Rin Itoshi is his younger brother. They used to be quite close with each other in their childhood. Sae was admired by Rin and he was the reason Rin started to play football. Sae and Rin used to play together and won many games together, they even made a promise to become the two best strikers in the world. However, they got separated when Sae was scouted to play in the inferiors of the Real Madrid. Four years later, Sae and Rin met again while the last one was training late. Sae then tells him that he will become the best midfielder instead of the best striker of the world, the thing that greatly affected Rin since his reason to play football had been his older brother. Sae then challenges Rin to play a one-on-one and tells him that if he defeats him he will retake that dream with Rin. Sae utterly defeats Rin and says he feels disgusted with him and the football of Japan, also telling Rin to never use him as a reason to play football ever again, leaving his younger brother behind while he stays in the field shocked and later at his home swears to destroy Sae.
Later on, their relationship fell apart and estranged, never seeing each other until the match between Japan U-20 and Blue Lock Eleven. Sae is absolutely indifferent to Rin and doesn't speak to him until they have another one-on-one, in which Sae tells him that he will never be able to defeat him as long as he keeps considering himself as "Sae Itoshi's younger brother". And while Rin tries his best to prove that he is better that his brother, Sae doesn't pay him attention. Ultimately, despite Rin successfully besting him in their fight, he still looked down on his brother and instead acknowledged his teammate Isagi, for his talent in achieving goals.
Blue Lock Players[]
Yoichi Isagi[]
During the Japanese Representative Match, Sae was surprised to find out that Isagi is the "Heart of Blue Lock". He was impressed by how he was able to plan different ways to score goals, to motivate his fellow teammates, and to inspire them to achieve victory throughout the match. Sae was also amazed on how Isagi managed to manipulate Rin into entering Flow, as well as take advantage of Rin's awakening to secure his defining chance for a victory shot. He even bluntly stated to Rin that Isagi will be the one to change Japanese football for the better, making him the first Japanese striker that he ever truly respected.
Oliver Aiku[]
Like with all members of the original U20 Japanese team, Sae had a very low opinion of Oliver, considering him to be very mediocre in his plays. Yet, he has shown to respect his clever tactical scheme in manipulating both himself and the heads of the Japan Football Union, which led to his endgame of entering Ryusei Shido into the game against Blue Lock Eleven, to prove to the world once and for all that Japanese football's "team-play" philosophy is defective and "egoism" is the key to victory.
Shidou Ryusei[]
Their first introduction to each other is when Sae tells Shidou that Blue Lock is too small of a cage for him. He tells Shidou to hand over his ego and go wild for Sae’s sake. Shidou first reacts angrily but is much more intrigued by the end of the scene. During the second half of the match, Shidou is finally subbed in. He and Sae pair up instantly, overwhelming not only the other team but their own teammates as well. A fellow U-20 player, Oliver Aiku even comments on how Shidou and Sae are a match made in heaven.
After an incident with another player, Shidou is rewarded with a free-kick opportunity to score. During this, he and Sae work together to plan the very best route Shidou can take to score his goal. Sae encourages him to think outside of the box and imagine his very best goal rather than the “realistically possible” goal. Shidou quickly comes up with his ideal goal and tells Sae that he says very exciting things. Sae tells him that this is the time to dream and to fall under his spell. Shidou responds by asking if he’s Cinderella now, then says he’s falling in love. Together, Shidou and Sae score the goal. After their goal, Shidou compliments Sae on his assistance. He tells Sae he likes him and asks for his number. Sae says he’ll give it over if Shidou scores a hat trick (a hat trick is when a player scores three goals in a game).
Shidou now looks even more excited than he was before. After a pass from Sae to Shidou, Shidou compares playing football with Sae to the feeling of electricity pulsing through his brain. Sae asks him to elaborate, and he answers by saying that he doesn’t really know, but this is the first time he’s ever felt that his freedom has been understood by someone. Shidou blushes and comments on his excitement again. Sae reminds him that he still needs to score his goal before he gets too excited. After Shidou scores his second goal, his teammates run toward him to congratulate him, but he ignores them and runs straight for Sae to jump on his back. He declares that he wants to play football with him forever and that with Sae he feels a ‘special sensation’ he's never felt with anyone else before. Sae reminds Shidou that he needs to score a hat trick before he’s rewarded, and even goes as far as calling Shidou a horny demon. Shidou responds to this by asking Sae if he can move in with him if he scores ten goals.
At the end of the U-20 match, Shidou scored his required hat trick and reminds Sae of his promise to give Shidou his number. Sae responds teasingly by asking if he can at least shower before he gives it over.
It's been noted that (aside from Charles Chevalier) Sae is the only player who can tame Shidou.