He's the longest camp of the 4 named in this zone. He was in the hallway leading to Archivist. I'd start with him first, then pick off the others while you wait for him to pop
Saw 4 mobs roaming through the Archivist room. Cleared them at least 8 times so far. Have yet to see this mob. Even cleared the previous room with the 6 a myrmidon of granite all 8 times. I was camping Glithos at the same time i was camping this mob. I finally saw Glithos. Still waiting on this mob. Saw one of the roamers go through the door that i can't open near the Rathe Archivist. He will wander out at some point so don't worry if you see him go through the door and you can't get him right away. EDIT: Forgot to add From March 8, 2013 to March 17, 2013 Rare Mobs and Faction Gains/Losses will be dramatically increased. Grind faction and get loot!. Hard to believe its even in place as of my post time let alone 24 Hours+ before my post. EDIT: Finally spawned in the hallway before reaching The Rathe Archivist room. Took the place of one of the 6 a myrmidon of granite.
The Rathe Librarian is not trackable. This is similar to another named in the zone, Glutch the Heap, who is not trackable (see my comments there). I was standing right on top of it using my level 85 druid with 175 tracking skill, and it did not show up on the tracking list. The Rathe Archivist, who was in the next room, did show up on tracking.
The Rathe Librarian was up and standing at a static golem spawn spot, just before the room that contains The Rathe Archivist. It was standing at approximately /loc 1018, -1025, -108 .
In addition, this NPC does not see through invisibility. I stood inside of it while invisible, to mark down the /loc and to confirm that it was not trackable.
spawns from 1 of the roamers in archevist room, and also spawns from hallway just southwest from. i assume any in the hall can do it, but for certain the middle SE one was it.