Words of Paradise at the End of the World: Aphrodite

Everything had changed. No one knew what had brought about this unexpected turn of events. Even though loneliness surrounded Choi Min-gi, life in another world gave him something new after he woke up, and he felt lucky once more. A smile still graced his face, beautiful beyond gender.

The protagonist looks like a cold, aloof femme fatale, but inside he's a goofy, carefree straight guy. No fixed pairing.