I-r0k is presented as an obnoxious user whose arrogance and unwanted presence make him a nuisance. He attempts to integrate himself into Parzival and Aech's party, but neither of them is willing to put up with him. He does not try to pursue the quest until Parzival finds the first part of the puzzle. He is ultimately a follower and not a leader like the active Parzival.
I-r0k does have a dark streak to him as well. When he realizes Parzival has made progress in the game, he blackmails both him and Aech, threatening to share their personal information on the gunter forums should they not tip him off on how to obtain the first key. When they do not agree to his terms, he makes good on his threat, though no one on the forums believes he actually knows either of these guys.
I-r0k ultimately makes Parzival look better as a person. Parzival is more passionate and active in the quest, not relying on cheats to help him through it. Unlike I-r0k, Parzival never resorts to low-blows or blackmail to get his way. He also has more friends than the solitary I-r0k as well; this, more than anything, proves to be Parzival's greatest strength in conquering Halliday's quest.