NPC Emptiness sub-quest
This is the next step in the line of quests you have to complete, to my knowledge. I did this next, so that's how I'll run the order. To attain this quest, it would seem you have to summon your NPC 3 times after completing the previous quest. After the third summon, you can go to a Rendevouz Point and and select "Talk about quests." This will trigger your NPC to mention being asked to investigate the emptiness, and he/she will invite you along. Once you've gotten this message from your NPC, no official quest will appear anywhere, but it will be triggered. The NPC will not mention it again.
After getting this message, head to a basic Promyvion zone, and enter. I went in naked because this leg of the quest is quite simple if you are careful. Once inside the Promyvion, you will see a Rendevouz Point to the right of you. Examine it, and your NPC will automatically be summoned. You now have 45 minutes to find a ??? on the first floor. It is really quite simple. Once you find it, your NPC is awarded with 300 EXP, and you will be offered a warp to the entrance of the Promyvion. You CAN select to keep exploring, but I just took the warp, given I was alone. You are now done with this leg of the quest.
Return to a Rendevouz Point in a starting city once you complete this, and your NPC will thank you for your help and present you with a Tactics Pearl. This acts exactly as a Signal Pearl, except it has 4 charges, and a 10 minute reuse. I am not sure if it can be recharged, but I have a feeling things like this will be given for other sub quests involving your NPC. Use it as you will, BUT DO NOT WASTE IT WHILE YOUR NPC IS STILL LEVEL CAPPED.