I have recently begun to suspect that Dot Pixis is might be in Isayama's sights for a gruesome death at some point in the series' future.
When he was first encountered by Eren and company, Pixis (in what was dismissed as at the time as him just being eccentric) commented that he would not mind dying at the hands of a "pretty female Titan". And, not soon after, the first Female Titan ever encountered appeared, trying to abduct Eren. After being revealed to be the Female Titan, Annie Leonhart was forced to encase herself in a crystal tomb to avoid questioning.
Now, jump forward to the present (or to an unspecified point in the series' future), Pixis (for whatever reason Isayama comes up with) comes to visit the imprisoned Annie. At some point during his visit (perhaps as he is preparing to leave), Annie's crystal breaks open, and she emerges, ready to escape her captors, and reunite with her comrades at their "Homeland" transforming to her Titan form, Annie begins slaughtering her guards, before bearing down on Pixis. Pixis is frozen in horror, but suddenly grins, and takes out his flask to take a swig from it. In his final moments, Pixis only laughs at the realization that he is about to be killed by a pretty Female Titan, before Annie devours/slaughters him.