Kummi

Kummi is a Het ship between Kuruk and Ummi in the Avatar: The Last Airbender series.

Canon
Kuruk and Ummi met at the New Moon Celebration. Kuruk was the current avatar from the Northern Water Tribe and had no desire to settle down as he preferred to bask in his fame. However, he met a girl named Ummi from the Southern Water Tribe at the New Moon Celebration when the tribes would come together. Kuruk described it as being love at first sight. The two spent a lot of time together and soon got engaged. Kuruk and Ummi had their wedding at the Spirit Oasis but before the ceremony was complete, Koh the Face Stealer snatched Ummi and took her away as punishment for Kuruk's previous arrogance. Kuruk spent the rest of his life and even afterlife trying to save Ummi from Koh who had stolen her face.

Fanon
Kummi is a rather popular avatar ship. Many fans like Kummi as a tragic ship. A lot of fanfiction writers have written stories about future avatars connecting to Kuruk and finally saving Ummi from Koh so that the two can finally rest in peace. Shippers of Taang have theorized that Ummi was eventually reincarnated as Toph and was born blind because she had her face stolen in a previous life. Because of this, Kummi is especially popular among the Taang shippers.

Trivia

 * Some fans thought that Toph Beifong might be the reincarnation of Ummi and saw Kummi as a precursor to Taang.