[Frontier]

Kind of like how Ghost and Saber ended up crossing over (and to a somewhat more random extent, Zero-One and Ex-Aid), I guess it's no surprise they had to fit in at least one significant crossover between Drive and W, and Teru made the most sense.

Although while they're still distinct shows there's always been kind of a synchronicity to W and Drive (which, I know, Riku Sanjo but still) what with being Riders that were kind of the most overt in being Superheroes who fight crime and stop monsters instead of the usual drama that comes with being a Kamen Rider. So I feel like they just gel well together.