Confirming the spawn time is a static 8 hours. Spawns in enterance to Veksar. Be cautious as passers heading to Veksar will stop and kill if up for sheer sport of destorying the item.
Ran across this guy below the LOIO near Veksar. I'm a 53rd level Necro and had a 53rd level Druid with me. We conned this guy: dark blue for sure. But it was all over in about 30 seconds (for us, not for this mob). He killed my pet in ***2 hits***, then chased me down and killed me in ***3 hits***. I managed to get 1 DoT off in the time he took to do both kills. He then turned on the Druid who only barely managed to Evac (and only because he was 3rd on the kill list).
You shouldn't put 70th level killing powers on a mob that cons dark blue to a 53rd level character.
Found this mob today at the entrance to Veksar in Lake of Ill Omen at -400, 0. Soloed him with no problem but it was a tough fight. I was at 50% health and 10% mana by the end. He hit me for max 207 and avg 110 with my armor class at 1309. Resists stuns and roots. Did not cast any spells. Dropped the Fabled Piece of a Medallion and the regular Piece of a Medallion.
Fight lasted a little over 6 min. Mob had 15k HP and hit me for 13.8k over that time. Fortunately I was able to keep myself healed and didn't need to use LoH. I recommend bringing a healer.