Ozymandius
This powerful NPC cropped up several times in encounters with the Dragonslayers.
During the Isle of the Abbey story arc in the Island Kingdom Adventures Era Ozymandius' group was thwarted by the Dragonslayers on Westemnet. Then later the Dragonslayers prevented his group from completing the Treasure Vault of Kasil Test on Thalion that both groups were competing in. Finally the Dragonslayers spirited away a dwarven child that Ozymandius was searching for, taking the child all the way north to a dwarven city Scylding, near Bozawa.
Then several years later the Dragonslayers visited the Island Kingdoms again during the Tenth Anniversary Game and interfered with Ozymandius again. During the fight his captain of the guard Ogmund the Strong was killed.
Dealings with the Dragonslayers became very complicated during the Trade Wars Era and particularly during The Missing Island story arc.
Notes:
Ozymandius is known to be a human. Blue Gill is reputed to be a Sahuagin. It is possible that, when he goes forth as Blue Gill, he is covered with a powerful illusion. Also, it is possible he has died and was reincarnated as a Sahuagin (how likely is that?).
On the other hand, is it possible that Blue Gill is a Sahuagin that, when he goes forth as Ozymandius, is covered with the illusion of a human form?
Either way, it seems he is trying to get his grip on the entire Spice trade.