Ritsu Sakuma/Mao Isara is the relationship between Ritsu Sakuma from Knights and Mao Isara from Trickstar.
They're very close childhood friends, and have stayed that way up until their high school years. They live in the same neighborhood, and Mao always has to bring Ritsu to school each day, often go as far to help him change and get ready, too.

Mao is usually the one to carry Ritsu on his back, but in Episode 23 of the Ensemble Stars anime, Ritsu carries Mao on his back, claiming that Mao is "relaxed when he is busy," so he forced him to sleep.

Ritsu often refers to Mao as "my cute, dumb Maa-kun," as Mao has a tendency to be almost comically oblivious to his feelings, leading Ritsu to talk down to him. Mao, on the other hand, accepts this without protest, and his automatic response when Ritsu calls him an idiot is to apologize and offer to kneel to Ritsu if it makes him feel better, even when he doesn't understand why Ritsu is mad in the first place.

In the prologue of the story Band Ensemble, it says that they both met in Elementary School. Mao was told to pick Ritsu up to go to school because Ritsu didn't attend for a while, and Mao kept doing it even years after.

The two have abbreviated forms of Japanese honorifics for each other (san, kun, chan, etc.). Ritsu calls Mao "Maa-kun," while Mao does the same and calls Ritsu "Ricchan." But unlike Ritsu, Mao stopped calling Ritsu by this nickname as they grew older, and just sticks with "Ritsu" when he talks with or about him.

Leo Tsukinaga/Izumi Sena is a relationship between two members of Knights, Leo Tsukinaga and Izumi Sena. Leo and Izumi have a very balanced relationship wherein they see and acknowledge each other as equals. On the surface, Izumi’s nagging and Leo’s childishness can make their relationship come across as more of a caretaker and his child than that of potential lovers, but this is far from true. Leo understands that Izumi’s nagging is his way of showing he cares. Likewise, Leo may act childish at times, but Izumi knows that Leo isn’t a child. Leo’s shown on multiple occasions that he’s smarter and more perceptive than people assume. Leo is constantly looking out for Izumi’s feelings because he sees how fragile he is underneath his fake pride, offering to become a throne to support him. Leo expresses his love mostly through words of affirmation. He consistently showers Izumi in praise and compliments him and doesn’t hesitate to say “I love you.” This affirmation is exactly the type of thing Izumi needs to feel loved, and he goes as far as saying that it’s the reason he was glad to be born in Lionheart. On the other hand, Izumi isn’t honest when it comes to verbalizing his feelings, but he expresses love through acts of service. Leo needs someone who’s willing to look out for and take care of him. He’s naturally forgetful and easily gets absorbed in composing. He wants Izumi to pay attention to and spoil him because he knows that’s Izumi’s way of saying “I love you” back. Leo and Izumi met during their first year at Yumenosaki Academy. Leo finds Izumi singing and laughs at how out of tune his voice is while claiming he “loves it.” The two become friends, with Leo composing songs for both Izumi and their unit, Chess. In the light novel story Lionheart, Izumi says that singing the songs Leo wrote for them together was his happiness. He keeps the songs on an iPod and considers it one of the things Leo left behind before disap