If I could go back in time and choose a thesis topic in a computer-science related field, it would be this:
The Quake III Arena Bot [pdf] (2001)
by J.M.P. van Waveren
University of Technology Delft, Netherlands
The author worked on the artificial intelligence of non-playing characters in Quake III for iD Software, and got to write it up as a Masters thesis.
NPC means “non-player character”, i.e. it’s a character not controlled by a human player. NPC’s may still play with you, though; they’re definitely not “non-playing characters”.