Ug is a Troll who resides in the Stronghold. Players help him during the quest Troll Romance, where they help him win the affection of Aga.
During the quest, players consider him to be a wimp. In troll tradition, in order to win the favour of a female, male trolls must fight and kill contestants. Since Aga's partner Arrg is strong and Ug is a weakling, the player must defeat Arrg for him, and pick a Trollweiss flower to prove Ug's love for Aga. After the quest, he manages to win Aga's love.
This article on an NPC has an associated dialogue page. Click here for a transcript of possible conversations with this NPC. Click here for a list of other transcripts that this NPC speaks in.
Most trolls are named after the first thing they eat; if the first thing eaten is unknown, they're named after the sound the thing they ate made, which in this case was "ug". This is revealed in a Postbag from the Hedge from November 2007, The trouble with trolls.
Even after you've completed the quest Ug still appears to be crying, although if you talk to him, he tells you that he's crying tears of joy.
An unused Ug NPC was added to the game that depicts him eating a chicken drumstick. What it was intended for is unknown.