[kamen rider bara]

like how the kamen rider v cinemas were much more mature and darker, are the ultraman gaidens the same?

[Baltan II]

No.

You seem to have a one-track mind when it comes to needing to find "mature and dark" toku, so in terms of Ultraman, let me close the case once and for all - the closest, and I mean absolute closest, you'll ever get to that in the franchise is Ultraman The Next, Ultraman Nexus, Ultraseven X, and maybe a couple episodes of Ultra Q Dark Fantasy and Neo Ultra Q. Neither of the latter are subbed but all three of the former are. That's it. Ultraman is ultimately not at all about the grim side of saving the world on a regular basis from monsters, but the positive hopefulness for a better future. It always has been and aside from the brief experiments in alternate media will probably continue to be.

[baltmatrix]

If you want something darker then I suggest you take a look at the new Ultraman and Ultraman Tiga manga series.

http://www.mangahere.com/manga/ultraman/

They are both a lot darker than what the shows are.