The most recent episode of "One-Punch Man" saw Saitama once again save the day by defeating the Deep Sea King. However, in the official promotional trailer for the upcoming 10th episode, titled "Unparalleled Peril," Saitama and the rest of the Heroe's Association will fight someone who could potentially destroy the world.

In the preview clip, Deep Sea King is heard complaining about his defeat. He states that he could have defeated Saitama if the battle was at sea where the Deep Sea King's powers might have been used to his advantage. He then remarks in confusion about someone being even stronger than him.

The trailer also gives the first real look at Lady Shibabwa, the prophet who is capable of foretelling every major attack and invasion threatening Earth. During the clip she is shown to panic and reveals that the new incoming enemy has been prophesized to bring about the destruction of the planet.

Fans of the original manga will recall this to be the beginning of the "Great Prophecy" saga where the Sky King invades Earth only to be killed by an even more powerful invader, the leader of the Dark Matter Thieves group known as Lord Boros. Lord Boros is described as a powerful alien with one eye and has a laser beam capable of destroyiing planets.

Lord Boros, in the manga series, was told two decades ago that he would one day encounter a man that would finally give him a worthy battle. Of course this would lead to him eventually fighting Saitama and it is this fight that Saitama will encounter someone who isn't immediately taken down by a single punch.

However, episode 10 might not immediatetly reveal Lord Boros and instead start by introducing the Sky King and his army only to end with Lord Boros killing the Sky King as his grand entrance to Earth.