A member of the royal family of the extraterrestrial Shi'ar Empire, Princess-Majestrix Lilandra Neramani was born on the Shi'ar homeworld known as the Aerie. The eldest heir to the Shi'ar throne was Lilandra's older sister, Cal'syee. However, for her crime of killing her mother and one of her sisters, Cal'syee was denied the throne and exiled into space. Cal'syee's younger brother D'ken was appointed majestor (emperor) instead.
Lilandra, D'ken's younger sister, served as Grand Admiral of the Shi'ar Imperial Guard, a cadre of super-powered beings that enforced Shi'ar law throughout the Empire, when she learned of her brother's insane plan to make use of the incredible power trapped within the M'kraan Crystal to grant himself omniscience. The Crystal itself was an interdimensional nexus leading to another dimension full of neutron stars consisting of super-dense matter that created extraordinary gravitational forces. D'ken was blind to the true danger that the Crystal presented, and mistakenly believed he could control its unleashed power. Lilandra opposed his plans in the Shi'ar High Council, and D'ken accused her of treason and had her arrested. D'ken then leaked word that Lilandra had attempted to kill him and usurp the throne, and civil war broke out across the Empire as a result. D'ken had Lilandra held captive aboard the Imperial Flagship whilst she awaited execution, but she escaped and fled in a small scoutship.
Lilandra sought help in stopping her brother from destroying the universe, and suddenly saw an image in her mind of the telepathic Earthman named Charles Xavier, who at that time was using his powers to unite much of the collective will of Earth humanity to create enough psychic force to fend off the invading alien Z'nox. Somehow, subconsciously, Xavier had found a kindred spirit in Lilandra, and this caused a psychic link to form between the two. Knowing of Earth and its large number of superhuman beings, Lilandra traveled there for help. She finally met Xavier, who used his powers to quickly teach her English, but she was soon captured by Davan Shakari, an agent of D'ken's, who transported her through hyperspace to the world of the M'kraan Crystal. Xavier's team of superhuman mutant adventurers known as the X-Men followed Shakari in time to witness the power of the Crystal unleashed. The universe was saved from annihilation by Phoenix, in actuality a primal force of the cosmos that had assumed the form of the X-Man Jean Grey, and D'ken was sent incurably insane and almost catatonic as a result.
The X-Men returned to Earth and were joined by Lilandra who was awaiting the decision of the Shi'ar High Council as to whether she should become empress, despite her having rebelled against D'ken. Lilandra and Xavier fell in love, and following the seemed death of the X-Men in Antarctica, Lilandra received word that the Council had ruled in her favor. Lilandra and Xavier left for the Shi'ar Throneworld together, whereupon arrival Lilandra became majestrix and Xavier became her royal consort.
After a time, Xavier returned to Earth on realizing the danger that the Phoenix posed. After Phoenix went insane and destroyed both a Shi'ar starship and the homeworld of the D'bari, who were part of the Shi'ar Empire, Lilandra demanded that the menace of the Phoenix be ended forever to safeguard the cosmos. Having familiarized himself with Shi'ar law, Xavier demanded Arin'nn Haelar - a trial by combat - to decide the fate of Phoenix, whom he mistakenly believed to be Jean Grey. The X-Men clashed with the Imperial Guard, but during the encounter Phoenix committed suicide in order to prevent herself from wreaking further destruction. Out of respect, Lilandra later attended Phoenix's funeral.
Later, Lilandra's older sister Cal'syee, now known as Deathbird, sought to regain the throne that she believed was rightfully hers. To that end, Deathbird allied herself with the treacherous Shi'ar High Council member Lord Samédàr and the alien races of the Brood and the Badoon in an attempted coup. The Brood were defeated with the help of the X-Men, but Deathbird succeeded in usurping the throne. Lilandra fled into exile with the Starjammers, and the Empire came under Deathbird's tyrannical rule.
During her time in exile, Lilandra found that she still commanded a great deal of respect from the leaders of other starfaring races, and thus was able to become the principal organizer of the trial of Earthman Reed Richards, better known as Mr. Fantastic of the superhuman costumed adventurers the Fantastic Four, for saving the life of the world-eater known only as Galactus.
Lilandra remained with the Starjammers as Empress-in-absentia, fighting to reclaim her throne. However, Deathbird had consolidated her base of power, and Lilandra was now considered a rebel. Soon after, Lilandra sensed over the psychic link that she shared with Xavier that he was in great danger as a result of overexerting himself after receiving massive injuries. Lilandra returned to Earth to take him aboard the Starjammer's ship where the advanced medical technology there fully healed him to the point where Xavier could walk once more. However, they were unable to return Xavier to Earth as the ship's hyperspatial drive had been damaged and the Shi'ar stargates were all now heavily defended in an attempt to capture Lilandra. Together, Lilandra and Xavier remained with the Starjammers and continued the fight against Deathbird's oppression.
Months later, the Starjammers learned on a raided space transporter that Deathbird was searching for a mythical power called "Phalkon". Lilandra confirmed the myth about this power source, and the Starjammers beat Deathbird to the map with its location. Deathbird was able to kidnap her sister Lilandra in turn, hoping to use her as bait to draw out the Starjammers, but Lilandra fought back against her sister. Lilandra would have killed Deathbird if the Starjammers not beamed her out. As it turned out, the mythical Phalkon was actually the Phoenix Force, currently wielded by the alternate future daughter of Jean Grey named Rachel Summers. Together, the Starjammers and the British super-team Excalibur defeated Deathbird and her Imperial Guard. As word spread about the Starjammers' victory, it inspired rebellions across the Shi'ar Empire.
Much later, the intergalactic teleporter Lila Cheney transported the X-Men to the Shi'ar Empire at the behest of Deathbird in time to see Lilandra regain her throne. Not all was as it seemed, however, as in reality a group of Warskrulls, using technology to allow them to duplicate superpowers, had captured and impersonated Xavier, using his telepathy to control Lilandra and the Imperial Guard. After the ruse was discovered by the X-Men and all the Warskrull impostors were exposed, Lilandra settled matters with Deathbird, discovering her sister did not want the throne anymore. During her time as ruling Shi'ar Majestrix, Deathbird had come to despise the responsibilities of maintaining the needs of an Empire as large as the Shi'ar's.
It would not be long before the Shi'ar Empire would face their greatest challenge yet. Machinations by the Supreme Intelligence, a being that served as the depository of all the knowledge of the alien Kree, working in conjunction with the malicious Skrull Empire managed to bring about a war between the Kree and the Shi'ar. Subtly influenced by the Supreme Intelligence by means of advisors who were, in reality, members of the Skrull race, Lilandra ordered the retrieval of some Kree artifacts from which Shi'ar scientists created a Nega-Bomb. Despite intervention from the Avengers, a team of costumed superhuman champions from Earth, who revealed the presence of the Skrulls to Lilandra, the bomb was captured by a group of Skrulls and was subsequently detonated over the Kree homeworld of Hala, killing 90% of the Kree population. Lilandra was left with no recourse but to claim the remains of the Kree Empire in the name of the Shi'ar and appointed Deathbird as viceroy.
On the eve of the ceremony that would see the Kree officially incorporated into the Shi'ar Empire, Lilandra had Xavier and some of the X-Men teleported to Hala, the Kree homeworld. There the X-Men uncovered a Kree rebellion, but although the dissident's leader helped them defuse a bomb that would have destroyed Hala's sun, Lilandra was still forced to arrest him, and the tension between legality and morality drove a wedge between herself and Xavier.
Later, when she learned of the many Earth heroes that had sacrificed their lives to stop the malevolent psionic being named Onslaught, Lilandra dispatched eight members of the Imperial Guard to protect Earth, even though her own Empire was under attack by the techno-organic alien race known as the Phalanx at the time. Fortunately, the Guard's Praetor Gladiator sent the X-Men to help defeat the Phalanx, preventing Lilandra and her empire from being assimilated into the Phalanx collective.
Soon after, the member of the Kree race known as Ronan the Accuser attempted to assassinate Lilandra by using the royal family of the Earth race known as the Inhumans as his assassins. However, the attempt was foreseen by Delphos of the Imperial Guard, and instead of Lilandra it was the shape-shifting Guardsman known as Hobgoblin, posing as the Shi'ar Majestrix, who was killed.
Lilandra's rule would again be tested when a meeting of the intergalactic council dubbed Earth as a threat to the entire cosmos, and it was deemed to turn the planet into an intergalactic prison. Lilandra tried the best she could to prevent this, but her efforts were in vain and the plan was put into motion. Lilandra dispatched her aide, Cerise, to Earth to warn the X-Men whilst she herself sought out Xavier. Ultimately, Earth's superhuman champions overthrew their planet's captors and freed their world.
Recently, Lilandra came under the mental possession of Cassandra Nova, the genetic twin of Professor Xavier who had usurped her brother's body. Whilst under Nova's control, Lilandra was forced to dispatch the Imperial Guard to kill the X-Men and also to plunge her Empire into Chaos. Nova then forced Lilandra to take her own life, but she was saved by X-Men members Cyclops and Xorn. The X-Men managed to convince the Guard of the true threat, and together they managed to defeat Nova and free Lilandra. However, the damage Nova caused to Lilandra's mind was great enough that Lilandra later attempted to assassinate Xavier, whom she still believed was Nova, in Mumbai, India. The attempt was foiled by members of the global search and rescue organization known as the X-Corporation. Lilandra's betrothal to Xavier was annulled, and she was returned to her people to recover.