Destiny - S1.E22

Armed with the power of the Masagami, Keita and Kuro synchronize and head into battle. The Masagami, having lost the ability to regenerate after being hit with Reishin's Exceed, merge their bodies into one to escape death and attain a new power. They battle Kuro, but ultimately are finally destroyed when Keita and Akane combine their Tera to give Kuro an ultimate exceed. Life begins to return to normal and Keita discovers that the Doppeliner system has not been stopped. Kuro, blaming herself for the Masagami's curse, decides to isolate herself from the human world and live in the Holy Land for eternity to put an end to the curse. Kuro bids a tearful farewell to Keita and leaves to return to the Holy Land. On the way to the Holy Land alone, she cries while professing her love for Keita; she says that she will not be able to see him again. As she does, Keita contacts and bonds with her through Syncro and she cheers up.