The Stenza participated in the titular battle.
Pictures reveal that Ranskoor Av Kolos is in a completely torn up, battle-ravaged state. Since the Stenza are the most likely candidates we have for an Arc Villain of the season, they may very well have comprised one side in the battle. Each of the nine distress calls came from a character in each previous episode.
No way is it a coincidence that there are nine episodes and nine distress calls. This is especially convincing because the Stenza are being pushed as the Big Bad, Krasko, Robertson, and Manish are still seemingly at large, and the Remnants were wasted in their debut episode.- This one is looking substantially less likely after the events of "It Takes You Away", as the Solitract is isolated again, Ribbons is dead, and Erik and Hanne are unlikely to be on another planet. Also, the Stenza haven't been brought up since "The Ghost Monument", though given that Heather wasn't mentioned once between "The Pilot" and "The Doctor Falls" (save for the blink-and-miss-it shot in "World Enough and Time") but wound up being the Deus ex Machina of the latter, it wouldn't be wholly implausible that they could be brought up again.
- Perhaps the antagonist has the ability to kidnap beings out of time and space, which would explain how the characters who survived "Arachnids in the UK", "The Witchfinders", and "It Takes You Away" could turn up on another planet.
- Jossed, although linking to the above Tim Shaw absolutely has the power to take beings out of space. However, it's unlikely that anyone came from Earth as the planet wasn't captured and Tim Shaw hasn't hunted in thousands of years.
The signals will be from/related to characters the Doctor has failed to save/spare in previous episodes
There's an unusual number of these this season, to the point it almost doesn't feel like a coincidence, including Grace, the Mother Spider, Frankie, Kevin, Astos, Eve Cicero, Prem, Charlie, Kira, Dan, Mother Twiston, Alfonso, Becka Savage, Ribbons, and the Solitract. The only episodes lacking this would be the second and third episodes, though one might argue the scientists of Devastation and Krasko might count, with the former being a retroactive example and the latter due to the Doctor preferring to return him to prison unharmed as opposed to sending him to his likely death in the distant past, given her disapproval of Ryan's use of the vortex manipulator. Though Doctor Who often has side characters fall by the wayside, what stands out is that this occurred in pretty much every episode this season and each example is usually fairly emphasized, with significant regret on the part of the Doctor. Thematically, it would work in with Thirteen's stated desire to help people. Ranskoor Av Kolos is an anagram for something
Look at that name. It's weird even by Doctor Who standards. Alternatively it means something significant when translated to a human language. The Remnants referring to the Doctor as the 'Timeless Child' will be brought back up
It was given a lot of prominence in its own episode, despite it never being addressed later or coming up again. The episode's antagonist will be...
- The Stenza.
- Partly confirmed. The villain is a Stenza.
- A returning character adversary, either from earlier in the season or earlier in the show.
- Human nature, as per the running theme of this season being that Humans Are the Real Monsters.
- The Daleks, if only so that the BBC can continue to use them.
- The Terrible Zodin.
- A villain who appeared in the Classic Series (1963-89), but not in the New Series.
- A new evil Time Lord.
- Whoever the Timeless Child is.
- The Master.
This episode sets up the events of the previous nine, and the Doctor and company must create a Stable Time Loop
Given how three of the antagonist alien races brought up this season (Stenza, Remnants, Morax) were/are evil warriors, the Pting was engineered as a weapon, and Krasko was a mass murderer, it's possible that all of them and more are at the titular battle. That's six episodes represented right there (the others being "Arachnids...", "Kerblam!" and "It Takes You Away"). Due to timey-wimey stuff, the Doctor and friends already encountered them after the battle took place, so now they have to — intentionally or not — figure out how to have set up those events with how this battle plays out. Somehow it will also set up the situation with the spiders, the Solitract, and Kerblam! as well.- The Pting could have been engineered as a weapon, certainly, but there's no confirmation of that in "The Tsuranga Conundrum". On the other hand, General Cicero could have fought in the battle.
Final results...
The theories about the Stenza are correct. Everything else is Jossed.