Vahar'ai
Vahar'ai was a biological event unique to the Kelpien species. A painful process resulting in the loss of the threat ganglia and the apparent suppression of fear responses, Kelpiens going through it reached an evolved state. The process was a crucial factor in the history of Kelpien-Ba'ul relations. ()

Early symptoms of vahar'ai resembled those of a cold, but later the condition escalated with increased heart rate, spiking adrenal levels, increased neural activity, and pain that would render the average humanoid unconscious. Their signature symptom was the inflammation of the threat ganglia in a unique way. ()

History
Around the 1st century BC, a significant portion of the Kelpiens were post-vahar'ai. Evidence suggested that these "evolved Kelpiens" were predators to the Ba'ul. During the 1st century, the number of un-evolved Kelpiens dropped to zero, bringing the Ba'ul to the brink of extinction. However, the Ba'ul bounded back, while the number of evolved Kelpiens dropped. It was theorized that the Ba'ul had used their technological advantage to lock the Kelpiens into subservience by enforcing the doctrine of the "Great Balance", allowing them to live while eliminating the threat they posed. As of the mid-23rd century, no Kelpien had experienced vahar'ai for over two thousand years. ()

By the 23rd century, Kelpiens believed that vahar'ai was a signal when they were ready to be culled or harvested for slaughter. Described as their death process, the condition was believed to be terminal, either through culling or madness. ()

According to Kelpien beliefs, to reach vahar'ai was a high honor, to be chosen by the "Watchful Eye" to maintain the "Great Balance". As a teenager, Saru asked his father Aradar what would happen if he reached vahar'ai by the next harvest, and Aradar explained the honor to him. ()

In 2257, Commander Saru of Starfleet became the first Kelpien to pass vahar'ai in over two thousand years. The off-world Kelpien's vahar'ai was triggered by sound waves from a communications attempt by a lifeform called the . After continuing to serve in the crisis through great pain, Saru requested that Michael Burnham sever Saru's threat ganglia, which would result in his death before madness came. However, his ganglia fell off by themselves, and his vital signs returned to normal. Saru reported that the innate fear he had always felt was gone. Although glad that vahar'ai was apparently not terminal, Saru was extremely troubled by what this meant for his people. ()

Shortly thereafter, a red burst led Saru's ship, the , to the Kelpien and Ba'ul homeworld of Kaminar. There, the Ba'ul went to great lengths to neutralize the perceived threat of a Kelpien having reached vahar'ai, including the attempted genocide of the Kelpien species. However, actions from the Discovery led to all Kelpiens undergoing the event. ()

By the 32nd century, Kelpiens no longer harbored biochemical traces of vahar'ai. ()

Alternate realities and timelines
In the mirror universe, Kelpians believed that vahar'ai was terminal and were ruthlessly culled by the Terran Empire when it came upon them. ()

In an alternate timeline created by  via the Guardian of Forever, she witnessed a Kelpian in the mirror universe go into vahar'ai before being taken away to be culled as  tended to him. Saru later informed her that he was about to go into vahar'ai himself and asked her to be the one to cull him. Instead, Georgiou informed Saru that it wasn't fatal and gave him advice on what to do based upon what she'd witnessed with the Prime universe Saru. As Georgiou lay dying from her duel with , she noticed that Saru had passed through vahra'ai which he confirmed. ()

After Georgiou returned to 3189, the Guardian of Forever informed her that since Georgiou had saved the life of Saru in the alternate timeline of the mirror universe, he would go on to save a lot of lives. ()

Medical conditions
Ceremonies
Physiology