Throughout the earlier episodes, there are hints that Reina has feelings for Taki, such as her unreasonable expression of frustration when Shuuichi mentions his disapproval of Taki-sensei to Kumiko. This is later confirmed when Reina confesses to Kumiko that she likes Taki in a romantic way.

Does Reina like Kumiko?

Now that they are friends again, Kumiko is probably the closest to Reina, since they intimately hug each other and share a strong bond of trust. They both have even said to each other that they love each other. Kumiko also says that she "will always stay by Reina's side" when Reina would compete against Kaori.

Are Reina and Kumiko canon?

Canon. Kumiko and Reina have a quite complicated relationship. In junior high, Kumiko saw Reina being upset and crying because they did not advance to the nationals despite getting gold. This prompts Kumiko to absent-mindedly ask if she really thought they could have advanced.