Killed him tonight. His ph (-61, -254, +311) is on the top floor (8th level) in the small room opposite where Reseacher Neskuisa spawns. His ph did not aggro from the corner (grp was shrunk and packed in corner) if your far enough in the opposite corner of the room. However, do not attempt to set up campfire in the corner as the named will aggro in the corner if he spawns. The guards also add, so have cc ready. The named is mezzable.
One clear in the adjacent large room there were no see invis, one time there was a SI mob and another time there was a SI mob that did see SOS.
Killed him with my raid warrior (lvl 84, 1k AAs, 31,000 hps, 4650 AC group buffed), my lvl 83 chanter bot, 85 cleric main, 81 cleric bot, 81 beast lord bot an 75 bot rogue. Had a 81 shaman bot and 80 SK main out of grp.
The max hit on my warrior was 2500ish w/defensive. Tenante is slowable, no special tricks, straight up dps fight.
Dropped: Dread Knight's Eyeguard Magic, Lore, No Trade Class: WAR MNK ROG BER Race: HUM BAR ELF DEF DEF HEF DWF TRL OGR HFL GNM IKS VAH FRG DRK Face Required lvl 80 AC 43 HP 500 END 490 Str 22+3 Sta 20+2 Int 13 Wis 8 Agi 10+2 Dex 33+3 Cha 19 Magic Sv 14 Fire Sv 26 Cold Sv 18 Dis Sv 32 Poi Sv 20 Attack 18 Dmg Shield 4 Dot Shield 2 Avoidance 2 Accuracy 7 Stun Resist 1 Strike Through 1 Backstab 9