Fans are now mid-way through Dragon Ball Super's Tournament of Power, a 48-minute battle royal that erases seven of the twelve universes. However, only eight universes are competing, with four of them exempt from it. But why are Universes 1, 5, 8 and 12 not competing?
It was officially revealed that it was due to those universes having a sufficient mortal level, with the other eight being too low. As a result, both Zeno's were going to destroy the struggling universe due to poor god management. However, Goku inspired the Zeno's to prepare a tournament instead, which resulted in only the losers being erased. However, it is doubtful that this is the only reason why these four universes have been exempt from the Tournament of Power.
As fans have seen from the tournament so far, all of the other universes outside of Universe 7 contain strong fighters with strange abilities, such as Jiren and Hit for example. Therefore, Dragon Ball Super fans should assume that the four universes exempt from the tournament also have equally, or even stronger fighters within them. This could be the real reason why these universes were left out of the Tournament of Power, as Goku will once again need the motivation to get stronger.
Basically, everyone in Goku's universe was weaker than him, so Dragon Ball Super creators needed to create other universes for Goku to find strong opponents. It has already been hinted by Whis, that there is a mortal stronger than a God of Destruction. However, Whis didn't go into the topic any further and it is assumed that the fighter that Whis was talking about, resides in one of those four universes exempt from the tournament.
Some fans believe that the fighter Whis was referring to is, in fact, Jiren from Universe 11, however, if that was true then Whis would have said his name. As a result, Whis's mention of stronger fighters out there points to those exempt universes. Goku is expected to win the Tournament of Power and if he does, he will likely want to fight the fighters in those other universes as well, which will force Goku to become stronger. If all the best fighters in existence were already fighting Goku in the Tournament of power, Goku will lose the need to improve. This is why those four universes were really left out; it's for them to be Goku's next challenge.
You can read up on the synopsis for Dragon Ball Super's current arc below:
"According to an invitation that Goku gets, Zen-Oh (Omni King) is starting a martial arts tournament between all the universes called "Chikara no Taikai" (Tournament of Power). But it is the beginning of universal destruction. Something awaits the winners and losers of this tournament. What will become of this fierce team battle between each universe's elite warriors?"
Dragon Ball Super's "Universal Survival" saga is part of the recent simulcast agreement that sites like Crunchyroll and Funimation have scored. Dragon Ball Super airs on Crunchyroll Saturdays at 7:15 p.m. CST. Toonami airs the English dub on Adult Swim Saturdays at 11:30 p.m.