[Blade Raider]

Kickback, you forgot Ninjaman. Not as a 6th, but as an Extra Hero.



We don't have a 6th every time. We have had additional rangers (or heroes in some cases) every time since Zyuranger with the only exception being Go Go V. The likes of Gekiranger and Go-Busters both had 2 additional rangers, but no 6th rangers. In the case of Ninjaman and Black Knight, they added to the products and stories in most of the same ways as a 6th would. Even some with 6 rangers have multiple waves of additional rangers (like Go-Onger and Hurricanger).

The fact is that marketing dictates additional rangers/heroes every year, regardless of numbers. 6th rangers are just the most common. It's how the shows handle these marketing mandates that really matters. The 6th ranger in the mid teens is a trope that is admittedly getting stale, but it's also the easiest to use.