So it seems like the Nick cartoon is wrapping up most of it's characters, list inside

[Chris]

Maybe I need to re-watch the episode but I thought Bishop said to Newtralizer that the reason he hated Utroms was because the Kraang brainwashed him in the past, not that the Kraang were still a threat? The peaceful Dimension X seemed to imply that the Kraang weren't a threat anymore and they really were wiped out during the Triceraton invasion. I wouldn't be surprised to see them appearing (Sub Prime seems to have more lives than a cat and honestly I'd love to have Gilbert Gottfried back one last time before the show ends) but they don't need to appear for their narrative to be complete.

Here's my thinking on this season;

Kavaxas Arc (4)
Acts as epilogue to the Super Shredder story
Last Shredder & Rahzar (both deceased)
Last Fishface & Tiger Claw (end of 2K12 evil Foot Clan, only Karai's Foot left?)
Final Farewell with Splinter (last chronological appearance)

Turtles Tots Arc (1)
No real wrap ups, ending may set up Monster arc
Last Splinter episode

Monster Arc (4)
Last Savanti Romero
Last Renet? (barring World's Collide cameo & possible Future arc appearance)

World's Collide Arc (2)
Last Dregg & Newtralizer (both deceased)
Last Bishop & Utroms? (possible appearance in Crossover arc?)
Wraps up Mona Lisa's story (but likely to appear again with Mutanimals)

Bebop & Rocksteady/Crossover Arc (3)
Last Bebop & Rocksteady
If still alive then last Kraang Prime/Sub Prime appearance
"Foot Walks Again" probably OT Foot but uf not then this will be last appearance/wrap up of the 2K12 Foot
Possible Mutanimals appearance

Usagi/Samurai Arc (3)
Stand alone arc really, not connected to main universe
First & last Usagi appearances

Road Warriors/Future Arc (3)
Likely featuring Verminator X (or Verminator Rex as they're apparently calling him) as the main villain
Possible return of Armaggon based on his Archie relationship with Verminator X and the popularity of the Future Shark trilogy
Likely appearances by Shinigami Mona, Mutanimals & other allies one last time (Renet?)
Final appearances & resolution for core cast - TMNT, April, Karai & Casey