Why were certain characters dropped from the first film and not in later films?

[d_osborn]

Both Keno and Casey were in Langen's first draft of SOTO. It wasn't a simple character replacement. To my knowledge, Casey didn't survive the first draft. It had more of a "save the environment" message.

[Masterpiece]

Originally Posted by d_osborn

Barron never had a trilogy planned. Barron said there was very little talk of a sequel during production of the first movie. From what I understand, he was basically pushed out of the process late in post-production, so I'm guessing he didn't put much thought into coming back.

I'm not sure why Keno wasn't brought back for TMNT 3. It looks like he was in Surf Ninjas that year, so it's possible that it was a scheduling thing.

Casey was in the first draft of the TMNT 2 script. The producers wanted the focus on the younger character.

Okay, 'tis true that Barron did not have a trilogy planned in mind.

But he did want the first film to be open-ended and yet standalone so that sequels were possible, but the film as a whole could still be viewed as a oneshot.

Good directing choice, because to me only the original film is canon.

I like to pretend the sequels are in a different continuity.