Confusion over Shredder and Krang's last appearance
 

After looking at the 96 season eps, i checked to see when exactly was Shredder and Krang last appearance. I thinks it's the "turtles to the second power" episode. they're standing with Dregg and company in that building and i didn't remember them going out in a big way, and if i am right why did the writers make this happen? Did they know at the time of production that this was going to be the last season of the cartoon and maybe the turtles would take Krang and Shredder out in one big last hurrah?

At that time, Dregg was the main villian of the show. However, the writers decided to bring them back in the season 10 3 part series that started with the Power of Three and ended with Turtles to the Second Power. Dregg brings them Earth so he can steal their powers to use against the turtles. Anyway, Shredder and Krang manage to escape and the saga is ended with Dregg and company along with Shredder and Krang being sent back to Dregg's shuttle which has became an inferno I believe.

They were sent into DImension X

Yeah it's been awhile since I've watched it. I don't remember them going to Dimension X though.

I believe Leonardo decapitated Shredder in one of the last episodes and Krang was stabbed in his eye by Raphael with one of his sais.

So is this like your trademark or something?

Hang on:

Didn't Shredder and Krang appear in "Divide and conquer" ?

And another thing:

Was Splinter cured of his mutation?

Nope, only in "Splinter No More", from the second season and it obviously didn't last.