In Season 14, the story centers around Nya as she develops her elemental powers of water, which end up being connected to a mythical creature deep in the sea. In the final act of the season, Nya is forced to become one with the sea in order to save everyone, losing her ability to remain on land with the other ninjas. While she may be gone for now, Andreasen hinted that her story is not finished yet. The new season will definitely further explore the elemental abilities of the ninjas, but it's unclear what villains or other obstacles they might be facing.
All the spoilers and hints about the new season so far have been revealed by the writers on Twitter, but there aren't many specifics. A few things that Andreasen revealed are that Jake, played by Nicholas Holmes, will be in Season 15, and that the character Kai will have "much love and romance in the year to come." One thing you can definitely expect is some sort of change with the character Cole, but it's unknown as of yet what will happen. Andreasen responded to a fans question regarding this by explaining that they did not take the decision of what to do lightly, but that he believes they did what would "honor Kirby best."
If fans are interesting in knowing more about what Season 15 might be about, they should definitely keep a close eye on the writers' Twitters. Along with their various comments about the show, this will also likely be the best place to find official announcements about "Ninjago" Season 15 when they are released.
