Seek out evidence left behind by the vampires. You're looking for bodies with white sparkles.
( 32, -8, -94 ) /waypoint 32, -8, -94
( 7, -18, -279 ) /waypoint 7, -18, -279
( -81, -33, -327 ) /waypoint -81, -33, -327
Return to Glaria.
Seduce a bar patron, and convince them to meet you in the alley. The bar patrons are the a lonely citizen in the bar of the The Jade Tiger's Den. Follow the one you talk to outside and down to one end of The Jade Tiger's Den ( -43, -24, -55 ) /waypoint -43, -24, -55 or ( -142, -24, -94 ) /waypoint -142, -24, -94. Two a vampiric ambusher will spawn. Kill them quick, as they despawn fairly quickly. If they despawn, go back to the bar and chat up another a lonely citizen and follow them.
Return to Glaria again.
She'll give you a Sun Crystal and ask you to search out the strange vampires at night.