Ogden is a Diablo I NPC, and gives new characters his standard "thank goodness you've returned, my friend" speech, and then fades into irrelevance. He does not buy or sell anything, but gives a quest reward for one quest in singleplayer, Ogden's Sign. If the heroes in Diablo ever slept or ate, he'd be a lot more useful.
Ogden is unfortunately (for him) one of the Diablo I NPCs that are believed to have been killed in the demon attack on Tristram.