Jefflyn is a ship between Katelyn and Jeffory. Jeffory was already married to another woman, and had a child named Abby. This ship died when Zane killed Jeffory for helping Aphmau, though Katelyn still does have feelings for Jeffory, or at least a great longing. This is evident from the episode 'My Golden Friend', where Katelyn confesses to Aphmau that one of the Demon Warlock's imps turned into Jeffory. She said she had wanted to hug him. Katelyn said he always knew what to say to her every time she was angry.
In the prequel series MyStreet Phoenix Drop High, Katelyn and Jeffory is revealed to have been in a relationship. However, the couple broke up during the MyStreet series, but continued to stay friends.