An NPC is a non-player character, as opposed to a real person (or whatever we are, playing this simulation.

They are programmed to be realistic and fulfil needs and purposes.

You might fall in love with one – is that a problem?

NO!

There are two possibilities:

• You fell for a real being, just as you would like, all good
• They are an NPC. which means you are just playing, and you get to play again, having learned