Here is a story I wrote on the subject last year during the candle of love event. It may help you understand who they are more.
Just who is this Astaroth the Shadowlord and why did he corrupt those three Shrines? People have asked this question of me ever since the Quest for the Candle of Love started. Well first off there are three Shadowlords and they represent the antithesis of the three principles of Truth, Love and Courage.
The two brothers represent Hatred and falsehood and their sister represents cowardice. If you have started the new quest you already know Astaroth is the Shadowlord of Hatred, but his brother Faulinei is the Shadowlord of Falsehood, and their sister names Nosfentor is the Shadowlord of Cowardice.
The Shadowlords are perpetual, undying, and near indestructible incarnations of Hatred, Falsehood, and Cowardice born from the Shards of the Gem of Immortality. They can only influence their victims and are unable to bring about any physical acts on their own. By whispering their thoughts and desires into their victims minds they slowly bend and twist those that are open to them into doing the acts the Shadowlords wish them to do.
The Shadowlords were first seen in the old “Ultima V: Warriors of Destiny Game (1988)”. In it Lord British who is on an expedition to the Underworld, to recover the lost Codex of Ultimate Wisdom, when he is captured by the Shadowlords. When Lord British disappeared Lord Blackthorn took power in Britannia, unfortunately the Shadowlords had been influencing him and twisted and corrupted him into a evil tyrant. At the same time the Shadowlords started to attack the virtues by persuading the people of the land to perform evil acts. meanwhile Blackthorn forced ruthless high-minded laws, based on his now warped version of the Virtues, upon the people of Britannia.
Honesty: Thou shalt not lie, or thou shalt lose thy tongue.
Compassion: Thou shalt help those in need, or thou shalt suffer the same need.
Valor: Thou shalt fight to the death if challenged, or thou shalt be banished as a coward.
Justice: Thou shalt confess to thy crime and suffer its just punishment, or thou shalt be put to death.
Sacrifice: Thou shalt donate half of thy income to charity, or thou shalt have no income.
Honor: If thou dost lose thine own honour, thou shalt take thine own life.
Spirituality: Thou shalt enforce the laws of virtue, or thou shalt die as a heretic.
Humility: Thou shalt humble thyself to thy superiors, or thou shalt suffer their wrath.
The Avatar was then summoned back to Britannia, forming the Warriors of Destiny with Some of those who had aided him before in his quests. They gather the known remaining shards of the Gem of Immortality, (The Gem of Immortality was used by Mondain the Wizard to control Sosaria. When destroyed it lead to the creation of the shards or mirror images of Sosaria in which we live.) and destroyed the Shadowlords, exile Lord Blackthorn and saved Lord British.
Some of you also asked what a gargoyle has to do with the start with the Quest for the Candle of Love? Well, in Early Ultima times gone by Lord British befriends the gargoyle Sin'Vraal, believing him to be a daemon. He convinces Sin'Vraal to give up his wicked behavior and escape from his servitude to the evil Shadowlord Astaroth. Though I am sure the use of him was also a nod towards Gargoyles becoming the next player race to the game this summer.
It has also been asked too what the Candle of Love is? the Candle of Love, Book of Truth and Bell of Courage are the embodiment of the three Principles that form the 8 Virtues. To protect these three powerful artifacts the construction of 3 keeps was ordered. The Empath Abbey protects the flame of Love, the Lycaeum holds the search for the Book of Truth, and Serpent's Hold should hold the Bell of Courage somehow. So there is a good chance in the future we will have to do something in Serpent’s Hold involving the Bell of Courage. These three items are powerful representatives of the three Principles that appose the Shadowlords and their desires for our lands. Hopefully they will help hold the Shadowlords back and away from influencing the minds of the beings that reside in our lands. So the reason that players need to complete the Quest of the Candle of Love is to drive back the Shadowlords with the Light of Love.
May the Virtues stay strong in all of you!
Does that answer your question?