If you're reading this, then you should know the ending of the game is a cliffhanger; A cliff hanger that made many angry, back in the day. If you want to know what happens, since the planned remake also won't have the true ending, then simply read the XIII comic books.

What? You thought the comic book aesthetic was just for looks?... No, XIII is an actual comic book that has been FINISHED. All your answers lie there and it's an excellent read.

You're welcome.

Apparently (I haven't done any digging to see if the user is pulling things out of thin air or not) if the remake sells well enough, they may attempt to continue the series in game form.

See point 1 in this response