Memoirs of Nershivia

(Sword and magic + stars and sea + interstellar war + Soviet, more original settings, high magic, not Western fantasy, not time travel, first person, the protagonist is female) A long time ago, a certain universe was ruled by three cosmic civilizations: the gods established by the gods who controlled the laws of the universe, the demons established by the strong men who resisted the tyranny of the gods, and the alliance established by various races who were fed up with the war between gods and demons and rose up to resist. The three major forces were hostile to each other, and a tripartite confrontation was formed for a while. Faced with threats from the abyss world and subspace, they both belonged to the order camp and chose to tolerate each other, so the era of peace came. But everything comes to an end. After millions of years of peace, the war sweeping the universe announced the end of an era...