Joshua of Britanny from the Resistance told you to talk to Sutek, who lives on a swampy island south of New Magincia. The mage will tell you how to defeat the Shadowlords, by retrieving the three shards of Mondain's gem from the Underworld and destroying them.
Dungeon Despise was somehow easy, but shall we risk the same in further dungeons? If you talk to Quintin of Farthing, you'll find that he loves to gossip, especially with his friend Telila of Britain. She will let you know that Bullwier of Jhelom knows about the Mystic Arms of the Avatar. In fact, Bullwier will relay you to Ambrose of Cove, a seriously injured warrior, that will inform you that the Mystic Arms lie under Dungeon Hythloth. This is good equipment to face the perils of the Underworld! Pity it is in the Underworld...
Before starting the quest, talk to Gardner of Serpent's Hold: he'll give you many important details about Hythloth, most important of all the fact that the Shard of Cowardice can be found there. The Councillor Hassad, captive in the dungeons of Blackthorn's Palace, knows the word of power to open Hythloth. Once the Mystic Arms and the Shard of Cowardice are obtained, talk to Lord Malone of Serpent's Hold to learn the name of one of the Shadowlords, and follow Sutek's instructions to eliminate it.
At the Lycaeum, Lady Janell, who already helped finding the Shrine of Spirituality, will suggest to talk to the twin sisters in Cove about the Shard of Falsehood. Leona will give you detailed directions to retrieve the Shard of Falsehood from Dungeon Deceit. Malifora of Moonglow, who already helped with the mantra of Honesty, also knows the Word of Power to open the Dungeon. Afterwards, go back to the Lycaeum and talk to Lord Shalineth to learn the name of another Shadowlord.
Dungeons Covetous and Wrong
Lord Michael of Empath Abbey will direct you to the gargoyle Sin'Vraal, who lives in the eastern desert, to learn about the Shadowlord of Hatred. Sin'Vraal will teach you not only the name of the Shadowlord, but also the two dungeons that connect to the section of Underworld where the Shard of Hatred is kept. One of the two is Dungeon Wrong, and Felespar, captive in Yew, is the councillor who knows its Word of Power. The other one is Dungeon Covetous; Annon informed you that the mother of a sailmaker is a councillor too: the sailmaker is Rew of Minoc, and her mother is Fiona, who knows the Word of Power.
The philosophy of Ultima
Notice the pattern of opposing dungeons and virtues, opposing shards and principles, and the location of the people who have information specific for the shards:
|Shard||Dungeon||Opposing Virtue||Virtuous town||Opposing Principle||Castle|
|Cowardice||Hythloth (Hi-Sloth?)||Spirituality||Skara Brae (Hassad)||Courage (+ Love + Truth)||Serpent's Hold (Gardner, Lord Malone)|
|Falsehood||Deceit||Honesty||Moonglow (Malifora)||Truth||Lycaeum (Lady Janell, Lord Shalineth)|
|Minoc and the Desert (Fiona, Sin'Vraal)
|Love (+ Courage)
Love (+ Truth)
|Empath Abbey (Lord Michael)|