Actually, I'm being a little unkind. De:Vadasy is unmistakably part of the herd of shameless Eva clones that stampeded across Japan in the late '90s, but this hilarious shot aside, it isn't quite as obsessed with checking off every single element on the Eva plot outline and character chart as, say, RahXephon. Although people do explode into Tang, and they even share a voice actress, but here she voices "Rei" instead of Misato.
Once upon a time this show's plot would have needed even less summary than Tokyo Majin, but ripping off Eva has gone out of style so here goes: The world's under attack by mysterious aliens and/or robots, and humanity's only hope is an equally mysterious robot that's not entirely under their control, and only likes being piloted by teenagers. But this time, the psychological and religious technobabble is (mostly) replaced with weird sleaziness. De:Vadasy (both show and robot) runs on sexual tension, and to their credit, it's not played as random, pervasive fanservice like Gravion or Godannar. Instead of sublimating their sexual tension in creepy ways, the characters act on it... albeit also in creepy ways. The show has a strong "adapted-from-porn-game" vibe, far more than a lot of anime that actually ARE.
This also means that everything that could possibly be a metaphor or innuendo is made completely literal. Check out one pilot's response to his robot getting hacked:
Writing this up has made me realize that a lot of modern mecha shows have gotten really bizarrely sexualized, but I'm not sure even Aquarion got this freaky. If you do hunt this down, don't expect much closure; De:Vadasy's three episodes are basically a pilot that never got picked up (and it doesn't look like the staff went on to do anything else of note), so there are trailing sequel hooks all over the place, but they're at least classy enough not to end on a cliffhanger. The story doesn't go anywhere too new, although swapping Eva's pseudo-Judeo-Christian symbology for Hindu is sort of interesting... or would have been, if they had much time to do anything with it. I can't recommend this per se, but there are worse things out there. For seekers of the weird and obscure only.