This page contains information regarding Star Trek: Lower Decks, and thus may contain spoilers.
During a second contact mission to the Galardonian home world, Commander Jack Ransom was bitten by a flying insect, and unknowingly brought a rage virus onto the ship. Ransom eventually infected a significant number of the crew, and in the resulting fight on the Cerritos, Shaxs fought many of the infected crew. When the battle was nearing defeat, he recommended detonating the warp core to Captain Carol Freeman, but his suggestion was denied. Dr. T'Ana instead found a potential cure for the virus within some oral slime that coated Ensign Brad Boimler, and when Freeman gave the order to protect the slime, Shaxs carried Boimler all the way to sickbay. (LD: "Second Contact")
When Ensign Sam Rutherford expressed an interest in changing jobs aboard the Cerritos, he was tested by Shaxs in Combat Simulation Smorgasborg, a simulation which involved a new security recruit facing down multiple Borg drones. Shaxs threw new recruits in this simulation to show them how to cope with defeat, but Rutherford astounded Shaxs by single-handily defeating each drone with the help of his cybernetic implant. Shaxs called Rutherford a natural born warrior, and welcomed him into security. However, shortly after this, Rutherford requested a transfer back to engineering. Shaxs was more than happy to let him go, saying that it was good to be true to oneself. (LD: "Envoys")
During a mission to Gelrak V, after an away mission did not go well due to a misinterpreted gesture, the Gelrakians launched an attack against the Cerritos. With the lack of buffer time, the crew was overworked and not completing their daily tasks properly, which resulted in ship functionality decreasing. Shaxs was unable to raise the ship's shields, and the Gelrakians successfully boarded the Cerritos in their attack. Shaxs helped defend the bridge throughout the attack. Once the attack was successfully thwarted, Shaxs led another away mission to the planet, in which proper contact was established, and there was no further problems. (LD: "Temporal Edict")
In a confrontation with the Drookmani, he advised aggressive action against the scavengers which were trying to claim Starfleet salvage for their own. He noted their claim of salvage as being ludicrous in nature, and was seemingly annoyed at Freeman's lack of action, favoring a more diplomatic approach. He begged her to let him fire on their warp core, and was visibly dismayed when Freeman didn't give him permission. When Freeman finally believed she'd exhausted all her options, she finally gave Shaxs permission to fire, but she'd given the order too late since the damage the Drookmani had inflicted by this point had disabled the weapons on the ship. The Drookmani were defeated when a corrupt isolinear core tore into the ship, and destroyed the ship from within. Shaxs was so happy with this victory that he gave Dr. T'Ana a kiss. (LD: "Terminal Provocations")
Shaxs took part in a covert mission to rescue Imperium Magistrate Clar from the Romulans. On stardate 57791.1, he, Chief Engineer Andy Billups, and Rutherford broke into a Vulcan museum to steal a 23rd century Romulan Bird-of-Prey. While they were successful, the mission was full of small problems, since Rutherford's actions were generally not his own, as his implant initiated multiple updates, causing him blackout, and lose control of his motor functions. In the end, the rescue of Clar was a success, and Clar attempted to have Shaxs and the rest of the bridge crew honored at a party, but due to the nature of the mission being unknown to the ensigns that Clar called forward to testify, the party didn't go far, and ended after only twenty-two minutes. (LD: "Veritas")
When the Cerritos received a distress call from the USS Solvang, the Cerritos investigated the call, to find the ship completely destroyed. The Cerritos was then immediately attacked by a Pakled ship, and crippled. Shaxs once more participated in fighting off several Pakled intruders. Rutherford came up with a computer virus that would disable the Pakled's computer, and Shaxs escorted Rutherford to the repair bay, where he blasted his way into the ship with the phasers of the shuttlecraft, Sequoia. Shaxs was successful in fighting off multiple Pakled guards, protecting Rutherford, as he uploaded the virus to the computer, but a complication from Rutherford's holographic creation, Badgey, resulted in the upload slowing to a crawl, and the initiation of a self-destruct of the Pakled ship.
Shaxs ripped the cybernetic implant off of Rutherford as it continued to upload the virus, which severely wounded Rutherford, but kept the upload going. He placed the unconscious Rutherford in the shuttlecraft, and pushed it out into space, saving Rutherford's life. Shaxs continued to fight the Pakleds until the ship exploded, killing him, along with everyone else on board. (LD: "No Small Parts")
The loss of Shaxs was felt deep in the crew of the Cerritos. His sacrifice was honored by the crew at his memorial, in which Freeman said they'd never forget what he did. Freeman later admitted that she had no idea how she would ever replace him. Dr. T'Ana had also hoped to start a romantic relationship with Shaxs before his sacrifice. (LD: "No Small Parts")
Shaxs was known to be very aggressive and was prone to favoring highly combative strategies in any tactical situation. He did not seem to fear any repercussions for what this action would have. He was rough around the edges with the crew as well, and not above making threats with anyone who displeased him. When he complained that barstools hurt his back, Billups simply told him that he wasn't sitting on them right, which made Shaxs say that he'd killed better men for less (or at least threatened to kill better men for about the same). (LD: "Moist Vessel")
Despite this, he was still very protective and supportive of the Cerritos crew. He believed it was good to stay true to one's self in Starfleet, and was a willing participant in many activities the senior staff took part in, such as poker. He also had developed affection for Ensign Sam Rutherford, whom he called "baby bear." Shaxs also possessed incredible strength, being able to run while carrying a person with one hand.
Shaxs was evidently at least a nominal follower of the Bajoran religion, as a realistic holodeck simulation of Shaxs, programmed from his logs, threatened his enemies with encountering the Pah-wraiths in Hell. (LD: "Crisis Point")