Singularity Bore

Singularity Bore flags you to be able to use the portal to Singularity Caul. Flagging consists of killing The Guardian of the Singularity. There are 4 possible routes to different Guardians.
Head south (down). You have the option of jumping down the shaft or taking the longer route route through the halls down to a room with 2 exits; East and West) Each of those two exits splits into a north and south route. The Southwest route is the shortest. Enemies in the Southwest route consist of Drudge Bloodletters, Ascendant Drudges, and various high level virindi.
The number of chain casting enemies can become overwhelming if you are not near maxxed magic defense. One way to accomplish this quest easily if your buffed magic defense is already around 250 to use a magic defense rare boosting magic defense to approximately 500. Almost no spells will get through a magic defense of 500 which makes killing the Guardian a matter of finishing before the 15 minutes on the rare are up. Once the guardian is dead you are flagged after you get the message about only opening the path to your doom.