From Diablo Wiki
Ormus is a rambling and half-mad old sorcerer, but there is information and truth in what he says. He proved lucid enough to use the Skatsimi dagger as part of a ward to protect the docks from the half-sentient, encroaching jungle. He is possibly part of the Taan mage clan, as Deckard Cain mentioned studying that particular clan, saying their magical studies were focused on Skatsimi rites and then mentioning Ormus as a good bet on using the dagger.
Unbeknownst to himself, Ormus is looked over by the Viz-Jaq'taar, who looks upon him with some suspicion. An agent of the Order called Natalya is known to have said: He seems to champion the cause of good, but who knows what shadow lurks within his soul? 
Deckard Cain is also unsure if Ormus just pretends to be mad to avoid attention to himself as a Sorcerer, or if he has ulterior motives. Cain is also surprised no one else has picked up on the fact he is a Sorcerer.
Diablo II NPC
Ormus gives a couple of quests and quest rewards, and in D2X he is the most popular NPC merchant in Act Three, simply because he is the closest to the waypoint and Town Portal locations, and thus the most convenient to trade with.
His wares are less popular to purchase, but he is the classic magical potion seller, and his inventory includes a few types of armor, along with staves, wands, scepters, scroll and tomes, and mana and health potions.
For more information about the Diablo II NPC Ormus, see:
|Characters & NPCs Import. Chars Rumoured Diablo 3 NPCs Diablo 2 NPCs Diablo 1 NPCs Minor A-K Minor L-Z Fanmade|
|Diablo III's Possible NPCs|
|NPCs of Diablo II||
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