Apparently you can bork your faction to the point where you cannot do this quest, but I don't know what faction he's on to fix it. One of my clerics however is KoS to Keylara who stands by Phenic. I was able to pull her off to do the turnins with Phenic, but as Lathin is also KoS to her (as were the two guards standing by the tapestry outside his door), I was unable to find a way do the turn in to Lathin at this time.
Apparently you can bork your faction to the point where you cannot do this quest, but I don't know what faction he's on to fix it. One of my clerics however is KoS to Keylara who stands by Phenic. I was able to pull her off to do the turnins with Phenic, but as Lathin is also KoS to her (as were the two guards standing by the tapestry outside his door), I was unable to find a way do the turn in to Lathin at this time.
Here are factions raised in the quest he gives out. Perhaps he is on one of these factions.
So Keylara and the dwarf next to phenic can be fixed by killing the SE tower in Sanctus Seru on the third floor. fair number of lvl 60 mobs that give good faction adjusts for those guys.
Lathin on the other hand is on the Magus Conlegium faction, and I've found no "easy" non-raid way to fix that one. I spent a substantial amount of time chasing down vigilum seniori's at 12 faction a hit, but they're very few and far between, and random all around the zone. Then I went to the second floor where folks kill the legionnaire's around the loop for lucid shard drops. while they're only 1 faction per kill they have a fast respawn, and I can take a group and run around that circle killing forever, and it's just a matter of time to get to dubious, and you can do your turn-ins to lathin then.
i am doing the shield quest and i fond him he is on the thrid floor of the casters guild loc is -960 -254 the way to get up there is to click the symbol on the wall and click it again when u do that turn left and he is in that room in the corner...