Balrons

Balrons, the kings of the Daemons! There is no foe more fear inspiring than these rulers of hell and darkness, even Dragons fear them. Their sheer presence is enough to let life around them wither and die. Normally, Balrons command hordes of lower Daemons into battle, but when they go into battle themselves, they are nearly unbeatable. Capable of extremely strong magic, equipped with tough skin and much strength, the Balron is a horrible enemy, to be avoided at all costs.

Thankfully, only rarely are they seen in our lands.

After their first appearance in Ultima I, Balrons appeared in Ultima II, Ultima III and Ultima IV, after that, they didn't appear anymore, which is curious. However, when remembering the Slasher of Veils in Ultima Underworld I, Balrons do still seem to exist, but mostly send their underlings into battle.

Lore
''Huge, leather-skinned daemon lords, the Balron are perhaps the most fearsome of the evil minions of Mondain. Armed with vicious barbed whips and the ability to cast devastating fire balls at their victims, these winged scions of Hell have proved to be the nemesis of the flower of Sosarian knighthood.''

- from "The First Age of Darkness", Ultima I

''Easily recognizable with its great leathery wings, the wretchedly evil balron ensures the success of its Herculean strength by using a sleep spell to render its victims helpless. Some have hypothesized that the spell is not real but that the fetid, putrid breath of the creature is so horrible that humans cannot resist the urge to escape it immediately by falling asleep.''

- from "The Second Age of Darkness", Ultima II

''It thou attempts to overcome these mightly warriors of the Dark, then thou hadst best be protected by all means possible. Anything less will mean thy instant destruction. These archfoes are so filled with evil, that they can hurl poisoned magic bolts from across the arena. The slightest hit may poison thy character and sap their vitality.''

- from "The Book of Play", Ultima III

''It is believed by some that all of these Marshals of Evil were destroyed when the Triad fell. If any do exist, it would be better for one to Quit life itself than to face the fury of a Balron. The ancient scrolls describe them as flying creatures which cast devastating fireballs as well as weave massive enchantments that once felled entire armies.''

- from "The History of Britannia", Ultima IV

Notable examples

 * The Slasher of Veils in Ultima Underworld I. This Daemon, while not explicitly stated, is because of its believable high power almost with deadly certainty a Balron. The Avatar has to use a lengthy ritual to banish it into the Void. Otherwise, all of Britannia would perish. Since no mortal spell or weapon could kill it. Armageddon could kill it, which most likely was a bug.

Trivia

 * Balrons are likely inspired by Balrogs.