Sentri, from Ultima VII
Age of Darkness
The Stranger encountered Sentri in the prisons of twentieth century New San Antonio during the alternate Terran timeline created by Minax's interventions in Ultima II. Once the hero battled through the gaol's guards and unlocked the door to the swashbuckler's cell, Sentri would volunteer a warning of his quick blade Enilno and for a sum of five-hundred gold coins, he would sell the legendary artifact to the adventurer, giving the hero the one weapon which could slay the enchantress.
The man's exact origins are difficult to pinpoint: he could be a native Earthman, or one of the many Sosarians who traveled through time doors before the Stranger did. It is apparent that Sentri traveled to Sosaria before the Time Doors disappeared. In centuries to come, the warrior would recall vaguely that he had met the hero who would become the Avatar on that dystopic Earth.
The swordsman eventually could be found in records of archaic Sosaria and was listed as a participant in Lord British's "Great Work", a log which chronicled the outcomes of several exploratory travels commissioned to provide detailed maps of the young king's domains. In this tome, Sentri (then known by the title of "the Seeker") recounts his ultimately failed quest to find the mysterious lost continent of Ambrosia. Although the young adventurer never made landfall on this mysterious realm, he nevertheless compiled several of the legends he had heard regarding it, relating tales of the mystic Ambrosian race and their powers of physical transcendence.  Later, during the Stranger's own quest against Exodus, Sentri could be encountered briefly at the Ambrosian Delight Tavern in Montor West, enjoying a drink of grog in the company of Shamino.
Age of Enlightenment
In the years of cultural and political revitalization that followed Lord British's christening of Britannia, Sentri rose to become the baron of the newly founded Serpent's Hold, where he became guardian of a portion of the tripartite word of passage needed to open the Great Stygian Abyss. During their quest in Ultima IV, the aspirant Stranger sought Sentri for knowledge of this word—after having been instructed to seek him out by Brother Zair of Cove. Assisting the hero in the pursuit of enlightenment, Sentri imparted his knowledge of one of the word's three syllables: "Cor."
Eventually, Sentri ceded his rulership of the Keep of Courage—apparently to the famed Sir Percy, who was granted the fief by Lord British in honor of his deeds combating the dragons of the realm. Despite no longer being a landed noble and having had but passing association in Britannia with the Avatar of legend, Sentri eventually became a target of persecution during the oppressive reign of Lord Blackthorn, and by the time of the hero's return in Ultima V, he had fled to the citadel of Bordermarch along with Dupre. Wishing to take an active hand in combating the dictatorial regime which had driven him into hiding, Sentri offered to join with the Avatar should the champion have need of his skills.
After the eventual defeat of the tyrant and the collapse of the Underworld, a series of earthquakes wracked the Britannian landscape, resulting in the complete destruction of Bordermarch when the island which housed it sank into the sea. Sentri, along with the lord and lady of the doomed keep, eventually came to resettle in Serpent's Hold, where the warrior assisted in the war effort against the gargoyles, awaiting the day when the Avatar would again return. Come the days of Ultima VI, when the hero did, in fact, sojourn to Britannia once more, Sentri again proved eager to fight at their side.
Age of Armageddon
Over the next two centuries, Sentri came to settle in Britain, earning his living by training others in the art of swordsmanship. While the ills that eventually came to haunt the realm grew into being slowly, Sentri seemed to have an inkling that all was not well in his sovereign's domain—and would comment as to the growing class inequality and Lord British's seeming ignorance of it is asked about it in Ultima VII. In this age of uncertainty, the fighting man would once more join the hero's party if asked, and would even waive his normal fees for training when traveling with the group.
It is not known, however, what befell Sentri following the destruction of the Black Gate, as he was not among those companions destined to accompany the Avatar to the strange Serpent Isle, and he later proved absent in the dark Britannia the hero returned to in Ultima IX—having either left the world for another or succumbed at last to his own death. No records exist to give exposition to Sentri's ultimate fate, although an artifact bearing his name could be found during the Avatar's last travels in the realm—a pair of magical leggings, which appeared to gift their wearer with some of the legendary swordsman's alacrity, allowing them to perform longer and higher jumps.
Ultima V: Lazarus
In Ultima V: Lazarus, Sentri vaguely remembered having met the Avatar on his previous journey, recalling how he had once assisted the hero with a syllable of the Word of Passage. Since that time, Sentri had become unhappy with his life as lord of Serpent's Hold, and had decided to renounce that position to Lord Malone, feeling himself more fit as a warrior than as a statesman. Sentri had joined Blackthorn's Black Company, feeling the young man to be a virtuous individual, and had performed many deeds of Courage in the current regent's name. It was with the loss of Lord British that Blackthorn's character had begun to change, and during the siege of Windemere, Sentri had finally parted ways with his former companion, becoming an outlaw forced to hide within the walls of Bordermarch.
- A "Dominic Sentre" (sometimes listed elsewhere as Santre or Sentri) appears in the rosters for the Society for Creative Anarchonism's barony of Bryn Gwlad—where Richard Garriott has been known to participate in the persona of Shamino Salle' Dacil. It may be that the Ultima character was based upon this person, given Garriott's penchant for giving his friends in the SCA in-game cameos.
- In Yoko Tanaka's manga re-telling of Ultima IV, Sentri is the leader of the paladins within Trinsic, and is the biological grandfather of the comic's protagonist, Deane. His daughter, the Lady Aila, had seemingly conceived a child through supernatural means, causing friction in her romantic involvement with Lord British at the time, and had died shortly after giving birth near Yew. Sentri plays but a modest role in the narrative which follows, commenting briefly on Deane's resemblance to his daughter when he passes through the City of Honor. 
- In earlier drafts of Ultima IX, developed under Bob White's tenure as lead designer, Sentri could be found taking refuge in Trinsic along with Katrina and Julia. In this version of the game, the stalwart fighter, together with Katrina, would have told of the circumstances surrounding the pair's escape from New Magincia and Serpent's Hold as they were each systematically razed by the Guardian's forces, as well as their investigations into the failure of Britannia's rangers and paladins to respond to calls for aid. Upon reuniting with the Avatar, Sentri would have been able to join the hero's party to continue the search for Trinsic's missing devotees of Honor.
- In a fan-patch that alters the dialogue for Ultima IX, the voice of Shamino informs the Avatar that Sentri has died in the war with the Guardian.
- "Ultima Dragons Internet Chapter -==(UDIC)==-". Facebook. Retrieved 2014-05-09.
- Sentri. Underworld Dragon's Ultima II Transcript. Ultima II.
- Garriott, Robert. Ultima III Clue Book: Secrets of Sosaria. Origin Systems, Inc: 1983. Page 43.
- Sentri. Underworld Dragon's Ultima III Transcript. Ultima III.
- Brother Zair. Underworld Dragon's Ultima IV Transcript. Ultima IV. "word".
- Sentri. Underworld Dragon's Ultima IV Transcript. Ultima IV. "word".
- Lord Malone. Underworld Dragon's Ultima V Transcript. Ultima IV. "deed, pay, valor".
- Sentri. Underworld Dragon's Ultima V Transcript. Ultima IV. "job, join".
- Morris, Andrew P. Ultima VII Clue Book (Ultima VII). Origin Systems, Inc.: 1992. Page 51.
- The Barony of Bryn Gwlad. The March of Precedence of the Barony of Bryn Gwlad. Retrieved: 2010-10-07.
- Tanaka, Yuko. Quest of the Avatar (Ultima IV). JICC: August 29, 1989. Pages 86-88.
- White, Robert. Ultima IX: Ascension - Plot Treatment. July 17, 1997. Page 34.