''The Madness Season'' was written by C S Friedman in 1990.

Centuries ago, Earth was invaded and subjugated by an alien race known as the Tyr. In order to make humanity more docile, the Tyr destroyed all of Earth's history before the invasion so that they would forget what a world ruled by humans might have been like. For the most part, the Tyr were successful. But there was one native of Earth who never forgot that old world.

Daetrin Haal (though he chooses not to admit it to himself) is an ancient vampire. For centuries before the Subjugation, Daetrin hid amongst humankind undetected. For the centuries after, he continued the masquerade, not just from humans, but from the Tyr as well. But, like him, the Tyr have a long memory and they ultimately find him.

Deemed by the Tyr to be a threat to their dominion over Earth, Daetrin is banished from Earth, doomed to live the rest of his many days on a distant research world. But he is a survivor. Cut off from what he needs to stay alive while being transported on a Tyr starship, his instincts take control and allow him to escape by jumping ship during a stop at a Medieval-level human colony world. There, he meets an energy being named Marra who also requires the life force of others to survive and is also able to change her shape.

Together, Daetrin and Marra travel through the Tyr-dominated worlds in an attempt to discover the origins of the Tyr which ultimately prove to be the key to destroying their empire.

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!!This book provides examples of:

* BeethovenWasAnAlienSpy: Daetrin's father was once an employee of the Library of Alexandria and personally saw it burn. Daetrin's mother was worshipped by the Helenic societies as a goddess (though we are not privy to which goddess she may have been).
* BelievingTheirOwnLies: The Marra who survive in hiding on the Tyr-controlled worlds often give themselves cover stories. Because their memories only span a few centuries, they eventually start believing their cover stories, to the point that they even believe that they are mortals who can die.
** Also Daetrin himself at the beginning of the book, who wished so much to be "normal" that for centuries he's convinced himself that he only suffered from a strange blood disorder, and that all memories of "supernatural" powers were just hallucinations.
* BizarreAlienReproduction: The Tyr reproductive cycle is based on their home planet's roughly century-long highly eliptical orbit. [[spoiler:At the planet's closest approach to their sun, the Raayat-Tyr, which effectively act as drones, enter a state of madness and enter the Tyr hive where they fight each other for the chance to reach the queen's chamber. If a Raayat mates with the queen, he will die. If he kills her, though, he transforms into the new queen.]]
* BodySurf: Marra is forced to survive this way when she first encounters the Tyr.
* DeathWorld: The Tyr Homeworld is perfectly habitable for two months out of its year. Unfortunately, that year lasts for over a century. For most of its elliptical orbit, it is covered in ice. For the brief period when it is close to its sun, it is a fiery hellscape.
* EnergyBeings: The Marra have no true physical presence and are instead anchored to the physical world by the life form that they inhabit.
* FakeWeakness: It is implied that many of the weaknesses that popular culture says belong to vampires were fabricated by their kind so that they could escape angry mobs relatively unharmed. Of particular interest is their "weakness" to wooden stakes. A properly skilled immortal is able to absorb the organic matter in the wood before it causes any damage to their heart. Unfortunately, some vampires wind up assuming that these weaknesses are the real deal, giving them a genuine aversion to such mundane things as garlic and holy water.
* FauxDeath: Daetrin's father taught him one technique to make him appear to be nothing more than a walking corpse. Unfortunately, his father took it too far and accidentally killed himself. Daetrin himself almost fell to the same fate.
* TheFogOfAges: Despite being a better shapeshifter and a neater feeder than Daetrin, Marra eventually forgets everything that happened to her more than a few centuries ago.
* FriendlyNeighborhoodVampire: Daetrin fought for Earth when the Tyr initially invaded. When they finally took over, he continued to teach later generations what had happened. During all that time, he has not drunk any human blood, thanks to synthesizing the necessary chemicals via modern chemistry. Plus, destroying the Tyr empire and liberating Earth, along with hundreds of other worlds, has to give him a few extra Karma points.
* GodGuise: One Marra encountered acts as the leader of a cult and uses his powers to convince the naive human colonists that he is a god. When he is finally "banished", he even does a fairly convincing impression of the Burning Bush.
* HealingFactor: Daetrin and Marra can both heal from what would otherwise be fatal injuries, so long as they have enough blood or energy to do so.
* HiveMind: The Tyr.
* HumanOutsideAlienInside: Most of the Marra encountered by Daetrin like to disguise themselves as humans, mostly because they've found themselves on human colonies.
** This is cleverly reversed [[spoiler:in the climax of the story where Daetrin transforms into a Raayat-Tyr in order to infiltrate their homeworld.]]
* HyperspaceIsAScaryPlace: The reason that the Tyr can travel between stars while everyone else collapses into a state of terror.
* ImmortalProcreationClause: The Marra are not able to breed. Or, if they can, they [[TheFogOfAges have forgotten how]]. Daetrin, as Marra describes, produces just enough life force to survive and no more, making him essentially sterile. [[spoiler:Subverted for Daetrin as it later turns out that, for his kind to breed, they have to be freely given blood rather than taking it by force.]]
* [[ImNotAHeroIm I'm Not a Hero, I'm a Coward]]: Daetrin, from the start, considers himself to be more a coward than a hero. Everything that he had done in his life, up to the events of the book, including his battles during the Tyr invasion, were coloured in his mind as selfish attempts at self-preservation.
* InsectoidAliens: Not just the Tyr, but also the beetle-like Saudar and one of the slave races ruled by the Tyr (though that race is more spider-like).
* LivingRelic: This is what makes the Tyr perceive Daetrin as a threat. The fact that he can remember what the world was like before they invaded is enough to banish him from the Earth. His parents also could have been considered such before their deaths, having witnessed the fall of European civilization into the Dark Ages.
* NinetyPercentOfYourBrain: This appears to be the main difference between Daetrin's variety of vampire and Marra's. When Daetrin transforms into, say, a wolf, his neural activity matches that of a normal wolf. When Marra does the same, her entire brain is used to house her consciousness.
** Actually none of the Mara consciousness resides in the brain. The Marra consciousness exists independently of the body, but they will activate specific areas of the brain in the bodies they inhabit as needed, because it's easier than controlling the body directly. So The Marra actually do only use a small fraction of their (body's) brain at any one time.
* NoBiochemicalBarriers: Averted. Daetrin, having evolved on Earth, is not able to transform on his own into a life form that is not native to his home planet.
* OperatorIncompatibility: The eyes of humans and Tyr respond to different frequencies of light. Because of this, all of the helpful labels that Tyr spacecraft use are completely invisible to humans.
* OurVampiresAreDifferent: We don't have just one kind of vampire in this book. Here, we've got two!
** Daetrin is effectively a blood-sucking vampire (though he doesn't care to admit it). Through the use of modern chemistry, he lived for centuries without requiring human blood, however this dulled his senses, and greatly weakened his shapeshifting abilities. Some fresh blood cured him of these handicaps very quickly.
** The Marra are energy vampires and do not even have to inhabit the same body at all times. They are also not native to this universe.
* PlanetOfSteves: All of the Marra are known only as Marra. Likewise, the majority of the Tyr, being extensions of the HiveMind, are designated only by the biological caste that they belong to.
* RogueDrone: [[spoiler: Frederick, at least during the times when he's not connected to the Tyr hive-mind.]]
* SocietyOfImmortals: The Marra initially had an entire incorporeal civilization existing on another plane of existence, before they were enticed into the physical world and occupied for centuries until they forgot how to return home.
* StopBeingStereotypical: The reason that Daetrin believes that turning into a bat is beneath him, even when he's trapped underground with no light source and the only way to navigate is through echolocation.
* SuperSenses: Daetrin and his kind are able to see into the infra red spectrum. As Daetrin re-learns his powers, he also gains a very powerful sense of smell and hearing.
* TitleDrop: The title of the book references [[spoiler:the mental state of the Raayat-Tyr as they enter the breeding season.]]
* VichyEarth: Humans pretty much have no rights except those afforded them by the Tyr. It's the same case with other races that were subjugated by them. What's more, if you're especially rowdy or subversive or just too smart, you're taken from the Earth and sent to some colony for the rest of your life.
* VoluntaryShapeShifting: Daetrin is able to transform into any living thing that has evolved on Earth (though he does not like the idea of turning into a bat because of the stereotype). The Marra are able to transform into anything, living or inanimate, period. One even managed to do a pretty good impression of the Burning Bush.
* YouAreNumberSix: Daetrin's full name is Daetrin Ungashak To-Alym Haal. It is not a true name but simply a Tyr numerical designation which every human on Earth must have.