Gray X Kira Strauss, The Cousin Of Mirajane
Kira Strauss is the cousin of Mirajane Strauss. Kira is an S class wizard, but no one knows her magic or anything about her. All they know is that she is the cousin of Mirajane, Lisanna and Elfman. This had gotten Natsu curious and the rest of team Natsu, except Gray though.
Who knows? Read to find out.