In one of Dragon Ball’s most morbidly realistic moments, Future Trunks comes back in time to warn Goku that not only of the threat of the Artificial Humans, but also the fact that Goku will die of heart disease in the future. Dubbed the “Heart Virus,” said virus stops Goku dead in his tracks, inflicting an intense amount of pain on the Saiyan’s body before taking its final toll.
Of course, this being Dragon Ball, Trunks manages to offer Goku a cure for the virus and he ends up surviving (for a time), but the fact of the matter still stands: there’s an alternate timeline where Goku dies from a mysterious illness, dooming the Earth.
10 Turning Super Saiyan Makes The Effects Worse
As evidenced during his fight with No. 19, turning Super Saiyan made Goku’s Heart Virus-related pain far worse. As soon as he triggers the form, the stress SSJ puts on the body essentially forces Goku down within seconds. Even transforming itself takes quite a considerable amount of energy, rendering Goku useless in a fight.
Interestingly, this is the first evidence fans have that turning Super Saiyan causes bodily stress. It’s likely that, after being cured of the virus, Goku took inspiration from this moment to pursue a method of Super Saiyan that wouldn’t put so much stress on the body.
9 It’s Contagious
Although he doesn’t outright say it, Piccolo very blatantly suggests that the Heart Virus is likely contagious, telling Yamcha to make sure he has some of the medicine himself in the event that he contracts it from Goku. While it seems strange that a Heart Virus, of all things, would be contagious, Goku was wheezing and hacking quite a bit before getting back home.
Even after he’s “resting,” Goku spends most of his time coughing and screaming through the pain. It’s not unreasonable to suspect that the Virus would be contagious, especially considering the fact that multiple people suffered from it in Trunks’ timeline.
8 The Heart Virus Was A Plague In Trunks’ Timeline
It’s only mentioned in passing, but Trunks has a very telling line about the Heart Virus. When informing Goku about what would happen to him, Trunks mentions that the Virus took quite a toll on the Earth’s population in his timeline. He specifically mentions how it was a global enough problem where a cure had to be mass produced and worked on.
With this in mind, it’s the Heart Virus can be seen as something of a plague from Trunks’ perspective. To make matters worse, just six months after Goku’s death, and around the time the cure was developed, the Artificial Humans attack and ravage the Earth.
7 The Dragon Balls Wouldn’t Be Able To Cure Goku
As the series goes on, the rules dictating the Dragon Balls start to lose their rigidness. By the end of the Majin Boo arc, it truly does not matter who lives or who dies, considering the heroes have two sets of Dragon Balls to choose from. Unfortunately, Shenlong and Porunga can only do so much, and curing a disease doesn’t fall under their jurisdiction.
As the Heart Virus is simply an organic part of Goku’s body (to an extent), the Dragon Balls wouldn’t be able to heal him. The logic there isn’t too sound, but it’s a necessity in order to ensure Goku stays down in Trunks’ timeline.
6 The Dragon Balls Can’t Bring Goku Back
Since the Dragon Balls can’t revive anyone who dies of “natural causes,” Goku is completely out of luck in the revival department. Worse yet, Shenlong had brought back Goku once before, meaning that, even if natural causes were fair game, he wasn’t coming back either way. What if, however, these rules weren’t in place at all?
Well, things still wouldn’t go Goku’s way, as Pilaf and company were gathering the Dragon Balls at the exact same time that the Artificial Humans were fighting Piccolo. Since Piccolo dies, the Dragon Balls go with him, permanently locking Goku out of any potential revivals.
5 The Butterfly Effect Stalls Goku’s Symptoms
An often under-analyzed facet of the Cell arc is the fact that Trunks ends up causing a butterfly effect in the main timeline. It’s generally believed that timelines in Dragon Ball more or less run concurrently with one another, the butterfly effect being a non-factor, but the very first instance of time travel in the series completely shifts the timeline.
Not only does the incident with Dr. Gero play out differently between both timelines, but Goku’s body manages to stall the Virus’ symptoms for a whole three years, only flaring back up under intense combat. Had the timeline not shifted, Goku and Vegeta would have been able to defeat Gero before he activated 17 and 18.
4 The Cure For The Virus Is Only Developed After Goku Dies
Unfortunately for Goku, he doesn’t live long enough in Trunks’ timeline to see the cure for his Heart Virus developed. As it turns out, the disease only spread like wildfire after Goku had already contracted it. By the time Goku had died, no one really knew the extent of the Heart Virus’ reach.
Most interestingly, the virus killed Goku, spread across the Earth, and was combatted within the span of six months. It’s possible the cure was developed after the fact, but considering how quickly the Artificial Humans wiped out most of the Earth’s population, it seems very unlikely that the world’s efforts weren’t immediately shifted towards stopping 17 and 18.
3 Goku May Have Contracted The Disease On Yardrat
One of the series’ most popular fan theories discusses the idea that Goku actually contracted the disease on Yardrat. Since Trunks’ explanation of the Heart Virus seems to suggest it came out of nowhere, and very shortly after Goku returned home to Earth, this can be taken as evidence that Goku’s outer space adventures ended up doing a number on his body.
With this in mind, that makes Goku the Heart Virus’ patient zero. Worse yet, this means that Goku infected the rest of the planet, likely by passing it onto the Z-Fighters who then passed it on to those around them, causing a chain reaction of infection.
2 The Heart Virus Isn’t An Epidemic In The Main Timeline
On the flip side, the greatest piece of evidence against the Yardrat theory is that Goku didn’t infect anyone during the three years he spent training for the Artificial Humans. Not just that, there’s absolutely no mention that the Heart Virus so much as manifested in anyone else during the events of the main series.
Logically, if the Heart Virus did become pop up with the same fury, it would have been mentioned in the Boo arc. For whatever reason, Trunks’ arrival not only stalled Goku’s symptoms, but it actively prevented the rest of the world from being infected. To think he didn’t want to create a butterfly effect.
1 Succumbing To The Heart Virus Is How Goku Is “Supposed” To Die
It perhaps goes without saying, but it’s quite easy to overlook the fact that Trunks’ timeline is the original timeline. It is the timeline that the Dragon Ball multiverse stems from. Had time travel never existed, the series would begin with Goku riding off with Bulma and end with him dying from the Heart Virus.
In an unaltered timeline, this is Goku’s ultimate fine. He comes back from Namek as the legendary Super Saiyan and reality takes its course. Goku is not invincible—he is a man like any other. It’s a morbid, almost humbling reminder that life isn't always fair.