First met in Mass Effect 2, Thane is a Drell Assassin who players recruit for the cause, and assuming he survives Mass Effect 2’s Suicide Mission, his story carries over into Mass Effect 3. It is heart-breaking nonetheless, because as players learn, he has an incurable disease known as Kepral’s Syndrome.

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Mass Effect: What is Kepral’s Syndrome

Kepral’s Syndrome is a genetic disease that can only impact the Drell, but unlike the Genophage in the Krograns, it’s entirely natural and man-made. It is named after the Drell, Kepral, who first diagnosed it. Essentially, the disease erodes a Drell’s ability to consume oxygen and stops blood from producing hemoglobin. It has been determined that Kepral’s Syndrome comes from cumulative long-term exposure to humid climates. Potentially, there is a connection here with a Drell’s lizard-like features. Lizards are often sensitive to climate and weather changes, and it would make sense here.

Unfortunately, it has become more and more of an issue for the Drell species in Mass Effect. It shortened their lifespan drastically, became the leading cause of death among Drell, and is not a pleasant way to go—with most losing the ability to breathe first, making each and every breath harder than the last until complete suffocation.

As a disease in the Mass Effect universe, there are a few other known key factors: it is not hereditary, it is noncommunicable, and it is not contagious. Drell born in humid climates have a higher chance of getting it.

Mass Effect: Can Thane’s Kepral’s Syndrome Be Cured?

No cure for Kepral’s Syndrome exists, but the Hanar have been working toward finding one for some time. This is important for a couple of reasons. It should be noted that the disease was first conceptualized as curable, given the advancements of technology in the Mass Effect universe. However, by making it uncurable, Thane Krios’ character adds a new layer of humanity to the game and also shows how even science in a far-future has its limitations.

It was pitched that perhaps the Reapers or Cerberus could cure it and use it as bait for Commander Shepard, but it didn’t pan out, reportedly, due to project limitations. Still, the whole idea of an uncurable disease in an assassin who has disassociated himself from his own body in a universe without a lot of spiritual humanity really takes his character to the next level.

As such, Commander Shepard cannot save Thane in Mass Effect 3. Shepard will eventually visit him in the hospital, but Thane is no longer in any condition to fight—needing daily treatment. Still, Thane (assuming he survives ME2) will fight and be stabbed by Kai Leng. Before his death, Thane will say a prayer of forgiveness, not for his past which he has already asked, but for Shepard.

Mass Effect 4 is in development.

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