FF11 to many of us is more than just a game, it's very much like the town we grew up in. So reading of one our past or present community passing is always very sad to me in a way I never really feel with any other game, whether I knew them personally or not.
In a way, because of how we see peoples avatars as overlays of themselves it's like the person passed and also the character that represented them.
I've had a friend I met in the game pass away many years ago, and also just lost contact with people that meant a lot to me in FFXI too. One of the great things about the nature of the games world is that while roaming around doing your daily routines, you'll get little happy moments of remembrance of them in memories triggered from those places.
Rest in peace Derfie and any other of our fellow Vana'diel kin that may have passed over the years.