Warning! The following contains spoilers for the Star Trek: Discovery episode "An Obal For Charon." Read at your own risk!
Star Trek: Discovery was an emotional roller coaster from start to finish, at it seemed the Discovery crew was going to say goodbye to one of their own. This wasn't just some miscellaneous crew member either, as Saru seemed destined for that great big...wherever Kelpiens believe they go after death. When the moment finally came Saru not only survived, but underwent a big change in his personality. He's no longer driven by fear, and that might land him in trouble.
The whole adventure started with the Kelpien co-captain feeling a bit under the weather, but assuring his fellow shipmates that it was nothing more than a common cold. Once it became apparent that wasn't the case, Michael forced Saru to go to Sick Bay and get to the bottom of what was going on. As the doctor examined him, Saru finally came clean with what was happening. He was dying, and it was, apparently, due to his biology.
The sickness is called "vahari" and it's a sickness that infects Kelpiens. According to Saru, those who aren't culled on his home planet and sacrificed to the predatory Ba'ul are believed to turn to a madness so bad that death is better. Once the action of the episode was over, it was time for Saru to end his run on Star Trek: Discovery. Michael accompanied him to his room, and agreed to cut his ganglia to prevent suffering.
Before Michael could cut the ganglia, the tendrils shriveled up and fell to the ground. Saru was confused, and suddenly felt a lot better. The two went to Sick Bay to find he was now completely better, minus the fact a piece of his body shriveled and fell to the ground. Additionally, Saru's persistent anxiety typical of his people was now completely gone.
It was a massive moment for Saru, who realized everything he'd been conditioned to learn about his people may be a lie. Kelpiens don't die after the sickness, and actually become much emotionally stronger once their ganglia falls off naturally. This knowledge was unknown to his home world, and could fundamentally change his species going forward. The problem is Saru can't share his discovery, as he's merely a refugee turned Starfleet and his planet is under General Order 1.
It's an interesting time for Saru, as he's now free of his constant fear. His new personality may make him blind to the fear he should feel if he were to break Prime Directive, even if doing so saves his species from their lifetimes as sentient livestock. Will Saru respect protocol, or will he set off for his homeworld and use his superior speed and strength he's been afraid to use before to bring down anyone who tries to stop him?