I just want to point out to all those that keep saying the author sucks at plot and what not. When something is serialized, authors are under contract, and this also means that they HAVE to write up to a certain number of chapters, but when their series gets axed, for whatever reason, they get notified WAY before the last chapter is out, making it so they have to think a way to bring the series to an end in X amount of chapters. When the series is not meant to end in X amount of chapters, but rather X+Y amount... THIS is what happens.
After episode 18, so, from 19 onward everything started getting confusing. In 18 we got a sudden change in perspectives from focusing on Yuuga's situation after Setsuna got back to being friendly with Rena, to then pointing out the effects that change also had on Aki, and that is fine, because Aki was ultimately the "Main heroine" of this story. The problem lies in that, right after said chapter, in 19 the story starts going on tangents to find a way to make an excuse to put Aki in the spotlight, but the story itself was made so after Blue comes Yellow, so the author had to wing it and make up an excuse for Yellow to be on Misaki, which makes totally no sense and has no foreshadowing AT ALL.
Again, another potentially good manga falls to the lack of popularity, and that's the sad thing, think about it, if this had not been axed (which looks like happened somewhere around chapter 18-19) the story would've followed into Yuuga and His color being Yellow that was put into him by Misaki at SOME point (Foreshadowed in the 'Because I want to be #1' chapter) and then culminated in Red with Aki, a color that She herself already had in her, maybe because Misaki wanted her to start loving herself which she clearly didn't... and realized that Rena ultimately was the answer to that dilemma, even though she probably hates the fact that she herself is not the answer. There was prolly going to be a LOT of drama around that last part, because that was foreshadowed as all heck in the start, and it all went poof.