Serena/Relationship

Yuzu Hīragi
Serena initially paid Yuzu no heed despite their similar appearances (though she was a bit shocked at first). However, when Yuzu told her the truth about Academia's cruel and immoral actions against the entire Xyz Dimension, she began to gain worries about her words and cooperated with her to find the truth from Shun. When she learned Yuzu was missing after the invasion, she was filled with great grief since it was because of her the invasion started. Due to this, she was adamant about finding Yuzu along with Yūya while in the Synchro Dimension.

Yūya Sakaki
Although they haven't interact much in the series so far, Serena and Yūya often interacts in the Manzai episodes. In the Manzai episodes, both have a good friendly relationship overall despite having difficulty talking with each other at first due to their contrasting personalities, especially since Serena often rebuff any kind of jokes or anything that she deems pointless conversation due to her serious disposition. Nevertheless, Yūya continues to be kind to Serena, encouraging her when it was her time to Duel out of concern for her well being. Serena herself always siding with Yūya if Shingo bring up conversation that requires her to choose between one of them and she believes that he'll be able to convey his belief through the Entertainment Duelling that he inherited from his father. Her faith in him also caused her to be quite strict on Yūya, fiercely telling him to stop being too cheerful and focus on his Duel.