ARGON - THE WATCHER
Argon, as he has been known on Abeir Toril, is a mysterious being of quite considerable power. He is a Planeswalker at the least and very possibly a demi-power in his own right at the most. He has identified himself as being in service to the Overgod Ao, as a recordskeeper of important events throughout the Multiverse. He had spent some time on Faerun millenia ago, and was known as Argon. He kept a hidden repository of knowledge and power on this world, and even as he spread his powerful mind throughout the Multiverse - he kept at least some of his mind trained on Faerun and so revealed himself to the Crimson Reavers when they managed to get through his defenses.
He revealed to the Heroes the detailed story of the Shadow Wars of the past, as Elmister had requested they seek information on. He prophesied that darkness was coming to Faerun and it was almost time for him to bring more of his attention to this realm. He also indicated that the Crimson Reavers would have a part to play at some future point in time, when the future of the Realms would hang in the balance. Because of this, he gifted each of the members of the group with a unique item of power - Each item once wielded by a powerful hero in the past. Each item was attuned specifically to the specific gifted person. He chose the items specifically for each person himself, as if mystically understanding which item would suit each person the best.
Only two of the items are from Faerun's distant past (The Bow of Auramar and the Sword of the Zephyr) - the rest being powerful items from other Prime Material Planes. Each item begins with fairly standard powers, but these abilities expand as the wielder becomes more experienced, in effect growing with the individual. New powers have been emerging as the group gains more experience, with no indication of how many more powers will be revealed and what their powers could possibly be.