| Hiro's powers resulted from mutations in his grandfather's DNA. These mutations were caused by the atomic bomb dropped on Hiroshima.
|| Hiro's grandfather was a survivor of Hiroshima and died of cancer. (The Crane)
|| - In an interview, George Takei strongly implied that Takezo Kensei is Hiro's ancestor. He says that through that legendary samurai, he is bringing a lot of good DNA to this role. This means that Hiro's DNA mutations were obtained from Kensei, not the atomic bomb.|
- • Takezo Kensei didn't turn out to be much of a hero after all.
- • This could be because of Hiro's manipulation of the past (kissing Yaeko).
- + Kensei probably did not produce any offspring while in Japan.
- - He probably did produce offspring in Japan, seeing that he's implied to be Hiro's ancestor, otherwise Hiro may have removed himself from existence due to his interference.
- + Adam Monroe was Kensei, and it has been confirmed he had only two children, both in Italy.
- There have never been any documented cases that mutations from exposure to nuclear energy have been passed on to offspring.
- + As long as something was changed in the gametes, it can be from the radiation.
- This is generally baseless, or at the very least a stretch.
• Theoretically it's possibly to pass along radiation-altered genes to offspring, but it's hellishly unlikely. It would have to had affected the one of 50 trillion or so cells in his body and would have had to alter enough genes of a half-genome (gametes only have half of the genetic makeup of the parent) to produce powers and still be compatible with another.
| Hiro's powers have not fully developed. When they do he will be able to summon anything from anywhere to any point in time.
|| + Many of the powers take practice and time to develop.|
• Future Hiro did not display such an ability. Had he possessed it, he could have brought Future Peter to him and Ando, rather than traveling to Las Vegas, or simply summoned present-day Hiro from the Homeland Security building. He may have not fully developed his powers in the period of five years, however.
- • Matt Parkman also did not display the full extent of his powers in the dark future. This may be from not meeting his father.
- • It might be considered rude to summon someone from their day-to-day business without asking permission.
+ Future Peter, who is considerably more experienced with space-time manipulation, was able to teleport Matt to Africa seemingly without actually going there himself.
- - Hiro already seems to have done this, moving Adam in and out of his coffin.
- + We don't know he wasn't simply stopping time (or rather, slowing it almost to a halt), shoving Adam back in, closing the coffin, and unfreezing time.
| Hiro did not actually change history when he time traveled to ancient Japan; events as they are unfolding now are exactly the events that occurred in the first place.
|| • This is a predestination paradox.|
- - This is not a predestination paradox. As it stands it's an ontological paradox. Hiro traveled back in time and acted in a way to create the Takezo Kensei myths, which he heard stories of when he was a child, which he then caused in the past, yadda yadda. There's no "source" of the information about Kensei.
+ In the stories that Hiro was told by his father, Kensei was Japanese, (like Hiro) not a gaijin. It seems he was destined to return to feudal Japan and become the hero.
- - However, Hiro's first interference in feudal Japan is to disrupt Kensei's planned ambush of the bandits he was hired to protect the village from. We see that this action is directly connected to Kensei receiving his famous sword and meeting the swordsmith's daughter (who was angry at him only for abandoning the village to it's fate, which was Hiro's fault). It seems fairly probable that before Hiro's interference, it was indeed this incident that set Kensei on the path to heroism. Indeed, Hiro himself points out that he 'broke history'.
- + Yaeko told Hiro that everyone will know the story of Takezo Kensei. She likely took license to make the story the way Hiro remembered it. Plus, in her mind perhaps, Hiro still saved Otsu as the story originally said.
+ The "Battle of Twelve Swords" fits more into the context of Hiro's time-stop ability than Kensei's regeneration; if Kensei had gone into the battle, it is unlikely he would have simply disarmed the opponents.
- - Hiro never indicated that the original Kensei simply disarmed his opponents (except by doing it himself).
+ This could explain why the depictions of Kensei in the Sword Saint documentaries looks less like Kensei, and more like Hiro.
- - Hiro had already been shown in 1671 (How to Stop an Exploding Man) when Sword Saint was released.
+ If a time traveling man in the future goes back to the past, then the present man would already see the changes his future self made in the past, considering they took place in the past. Basically Hiro, before he went to the past, would have to be living in a world in which his future self already "altered" the past, because it took place in the past and would have already happened. So throughout Hiro’s entire life the events that took place with Hiro in the past, had already taken place, and all the effects of that would have already been weaved throughout the current timeline before Hiro even decided to go to the past.
- • That's basically the definition of a predestination paradox.
| Every time Hiro time travels, he causes a catastrophe such as the bomb that explodes in New York and the plague that Peter and Caitlin saw.
|| + In the graphic novel String Theory, it shows he went back in time to stop Sylar from getting Claire's power so he could be killed. Doing so may have made Peter the exploding man instead of Sylar.|
- - In the Five Years Gone timeline, Nathan, or Sylar pretending to be Nathan, told everyone Sylar was the bomb, when it was actually Peter. This could have happened in Future Hiro's timeline.
+ Hiro teleporting forward in time prevented him from stabbing Sylar in the explosion future.
+ Hiro made it worse when he accidentally teleported to feudal Japan. There he met his childhood hero Kensei/Adam. He couldn't believe Adam was a drunk, pillager, and only thought of himself. So he turned him into the hero he read about but he betrayed him by kissing his princess. During the fight and before the explosion, Adam told Hiro he would pay for what he did.
- + Bob said Adam was the first and he said Adam wanted to help the human population by ruling them through enslavement and punishment (or something to that degree). Maybe if Hiro hadn't gone back to Japan and met Adam and then accidentally betrayed him, none of the future Peter and Caitlin saw would exist because Adam wouldn't want to seek revenge for hundreds of years. Adam may always have been the one responsible for the release of the Shanti Virus on the world. If Adam can heal from the Shanti virus, then Adam would have nothing to fear from an outbreak.
- - One of the side effects of the Shanti virus is the inability of evolved humans using their abilities. Thus, Adam would not be able to use his power if he came in contact with the virus.
- • In the episode Truth & Consequences, Mohinder finds out that Claire's regenerative blood is a cure for the virus. So that means Claire, Adam, and maybe Peter are immune to the effects of the virus.
- • Claire's blood is only a cure for the virus when combined with Mohinder's antibodies. It is possible that someone with the ability of regeneration could resist the effects of the virus much longer than someone without it (as it is not explained exactly how the virus negates abilities; if it is damaging whatever cells are responsible for powers, constant regeneration may be able to hold it off, possibly indefinitely, in a "dormant" state), but unless we learn more about how both the virus and powers work, it is impossible to say whether Claire, Adam, or Peter could survive.
- + Adam tried to release the virus in the present-day, in spite of this.
- • Claire's blood and Mohinder's antibodies were the cure.
- - Hiro has time traveled many times without causing any such events: going back to save Charlie from Sylar and failing, trying to capture Usutu.
- + But Usutu was killed. That qualified as a catastrophe. (But that was actually not time travel when he went to get Usutu.)
+ Hiro traveled back in time, retrieved the catalyst from his mother, Ishi, and then allowed the catalyst to fall into Arthur's hands, thus eventually completing the formula.
- Peter and Arthur also had the ability to time travel, yet no such catastrophes occurred. Why would they in Hiro's case?
- Hiro time traveled to fix Ando and Kimiko's relationship.
- Hiro time traveled forty-seven times to save Tadashi.
- Hiro time traveled to save Charlie.
- Hiro time traveled to retrieve a film for Samuel.
| Hiro could travel between alternate universes/timelines.
|| + Hiro has gone to futures that did not happen. They could be futures of alternate universes.|
- It is possible that the future that he visited was a product of him being "out of the equation" as he was able to prevent Claire from being killed, but didn't stab Sylar (as he was there in that timeline).
- - Technically, he would still be out of the equation until he reappeared in the future. Therefore, it makes no sense how Future Hiro would still even exist.
- - Therefore he had to have then gone back to the past of that future, in order for Future Hiro to exist.
+ Hiro has traveled not only to futures that did not happen, but to futures that were inconsistent with events that had already happened in the main continuity. For example, in "Five Years Gone" he went to a future in which it was implied that Sylar had taken Claire's power and survived the explosion, even though Sylar had been stopped from taking Claire's power several episodes earlier.
- - Sylar was shown taking Claire's power in this future, indicating that he had not done so earlier.
- + However, Future Hiro told Hiro that Sylar hadn't been stopped because Sylar had taken Claire's power before, which makes it unclear why Sylar took Claire's power in that future.
- • Future Hiro warning present Hiro changed the past, so the future as he remembers changed after that.
+ It is possible he could develop this power. Matt has discovered more facets of his ability he didn't realize before; so could Hiro.
+ Unless he can, Caitlin is lost for good.
• If Hiro time traveled to past and changed history, he would cease existence like all of future characters did. But past characters would eventually become new present-day characters, which didn't exist before. The history changed, but the influence from now-not-existing timeline remained.
- The one solid example of Hiro going to the past that exists in canon is his going back to try and save Charlie. It obviously existed in the "original" timeline (Ando didn't travel with him, but the picture of Hiro and Charlie from six months earlier still existed to him), so Hiro must have traveled to the past of the "real" timeline. Plus, when Hiro arrived back at the Diner, Ando still had seen the picture, and Hiro still had been to the past. So either Hiro manipulates time to a degree that is completely at odds with any modern (or even philosophical) idea of time travel, or the (seemingly omniscient) third-person narrative we see is flawed (which would render any theory pretty much moot).
| All of Hiro's time travel ventures were predestination paradoxes.
|| Hiro and Claire were already in Isaac's comic book. (Our Father)
|| + Hiro became Takezo Kensei when he traveled to 1671.|
- That's an ontological paradox, not a predestination paradox. See the Talk Page for an explanation.
- + Actually, it's both. Predestination paradoxes and ontological ones often happen at the same time.
• Not all of his time traveling instances would be predestination paradoxes; only the trips to the past would be. But this was probably implied in the theory.
| With sufficient practice, Hiro would be capable of altering space-time around others, such as sending them into space with voids. If he was supercharged, he would obtain nigh-godly powers.
|| + Hiro has been shown altering space-time around others, reversing and accelerating time on objects such as clocks and bullets.|
+ Future Peter was able to send Matt to Africa.
- • It's possible that Future Peter stopped time and teleported himself and Matt to Africa, then teleported back alone.
+ It's assumed that Ando can boost your power from thousands to millions of times over. On a being whose power allows him to bend space-time to his will, this could allow him powers superior to those of Doctor Manhattan, such as converting air into gold, or possibly moving the entire planet through teleportation and time-travel.
- - Supercharging space-time manipulation would not lead to transmutation of elements.
- • If there is indeed some unknown force stopping Hiro from creating time paradoxes, it would likely stop him from moving the planet.
| Hiro will become a villain.
|| + Hiro has many elements which could make him a tragic but powerful villain. An extremely powerful ability, skill with a weapon,various things that could cause him to snap if destroyed, idealism, and the ability to look badass.|
- Hiro has strong morals and codes and would not try to hurt people, and besides, Heroes can look bad ass too.
+ Hiro has suffered greatly since the show started. Losing his father and both the women he loved. If Adam can changed back to evil after losing Yaeko, maybe losing Charlie again will do the same to Hiro.
| Matt Jr. restored Hiro's ability completely, but because Hiro stopped time with him immediately after, it broke at once.
|| Masi Oka stated in an interview that Hiro's terminal condition is caused by taking others into frozen time.
|| + Hiro stopped time with baby Matt and couldn't teleport.|
+ Hiro had a headache after he froze time with Ando in Isaac's loft.
+ When Hiro attempted to stop time with Ando near Building 26, he had both headache and nosebleed.
+ Hiro has recently regained the time traveling aspect of his ability, but couldn't control it.
| Hiro will die alone.
|| + Hiro refers to Charlie as his Gwen Stacy, Spiderman's true love. But she married another.|
+ Hiro's other love Yaeko loved another man, had children and died.
+ Hiro's obsession with saving the world could interfere with his love life.
| Hiro damaged the timeline by saving Charlie. His little talk with Noah changed Noah's actions in some detail.
|| + The butterfly effect works in mysterious ways.|
- Noah only said love is a messy business. It doesn't seem enough to affect the timeline in any way.
- Hiro has interacted with others in the past before - with his 12 years old self and with his father in 1992, but it didn't seem to affect history.
| Hiro will become the Hiro from the explosion future.
|| + Everyone is aware of specials like they were in explosion and exposition futures. Hiro may need to protect specials again.|
+ Hiro lost Charlie again.
- • Not the way he lost her before.
- The government has been aware of evolved humans since Nathan revealed their existence to them. The government could do something akin to witness protection.
| Hiro and Ando will join forces with Micah and Monica.
|| Hiro and Ando's superhero team is based on the idea of using super powers to save others, just like Micah's team.
|| + The fact that Monica might possibly be the super hero St. Joan and the rebel group might make a family style Fantastic Four parody.|