This is a Space Opera trilogy by Jean Johnson, consisting of A Soldier's Duty, An Officer's Duty, and Hellfire.Ia is a precognitive, who foresees a galaxy-wide cataclysm three centuries in the future. In all the possible futures, only one comes out differently, and Ia must give up every possibility for her own life to make sure that it happens.She must abandon her dreams of a career as a singer and musician, and join the Space Force, first as a Marine, then into other branches. She disobeys orders and conceals vital information from her own superiors. She literally wades through the blood of friend and foe alike, fighting through a genocidal war that she could have prevented. She leaves her family and homeworld in the centuries-long grip of an oppressive theocracy, all in the service of iron necessity, because if she allows anything else to happen, everything in the galaxy will die, eradicated as though they'd never been. She will sacrifice all that she would or could have been to become the Prophet of a Thousand Years, ensuring that the galaxy and all the sentients in it will have a future of more than three centuries.
Dodge the Bullet /Implausible Fencing Powers: Ia parries not just bullets but lasers with her sword. Justified by her precognitive powers; she knows beforehand where the projectile is going to be, so she can put her sword in the way.
Energy Beings: The Feyori, who use their powers to meddle with matter-based intelligences as part of a game of their own.
Heavy Worlder: Ia is from a 3.2g planet; her consequent strength and reflexes serve her well as a Marine.
Psychic Powers: Ia has massive precognitive powers, along with lesser talents in telepathy, pyrokinesis, electrokinesis, telekinesis, and biokinesis.
Power Incontinence: When people touch Ia for too long, they are likely to be pulled into her visions, which is invariably a rather traumatic experience.
Red Baron: Ia gets the moniker "Bloody Mary" after she ends up covered in Ludicrous Gibs during her first combat action. "Bloody Mary!" was the first thing out of her CO's mouth when she saw the mess. Then she gets covered in blood again, this time wearing her BDUs, when the prisoners they took stage a breakout, and that's that.
Star Trek: Human habitable worlds are called M-Class (with a note that it was so embedded in popular culture at the beginning of space travel that scientists just went along with it), while an apparently unwinnable training scenario is called 'a Kobayashi Maru'
Stable Time Loop: The Immortal was born two centuries in Ia's future, then cast back in time 15,000 years by the Feyori. She rescued a group of humans from tectonic upheavals on Earth and transported them to a distant planet, which eventually became the V'Dan Empire, and founded a religion there predicting Ia's coming as the Prophet of a Thousand Years. This also allows Ia to steal designs for future technology from the Immortal's records.
"The Reason You Suck" Speech: Captain Ia gives an epic one in Hellfire, as she explains to a disobedient subordinate how, by continuing to fire after she ordered him to stop, he doomed the entire galaxy. How only through one of his comrades giving up everything he ever could have been to take over a dead man's life was the total annihilation of every sapient who would ever live in the Milky Way averted. And how, because of his actions,despite all she could do to fix the situation, 720,593 people who otherwise could have been saved will die horribly.
"You will be given a list of these names to contemplate in your spare time. You are free to ignore it if you wish, but understand that I cannot. "
Unusual Euphemism: A variety of "V'Dan" curse words substituting for many four letter words, but also more unusually replaces 'ass' with 'asteroid' in all circumstances.