Well, at least the setting explains most of it. Our main character's not programmed to be very smart. He's just an expendable minion, so he kind of has an infantile worldview of things and can't be very scheming as a result. He's trying to infiltrate the super sentai organization, but he can't help but slip up and require assistance from others due to his simplemindedness. He has the mindset of a evil minion, which is world domination as an evil organization, and it shows in his mannerisms. He's not Light in Death Note or Vincent Freeman in Gattaca, where the main thrills of those shows is the tightrope between the main character and the organization he infiltrates. This show is definitely more shounen, more free-flowing, where Fighter D fights while also experiencing friendship, relationships, etc. He has his own righteous ideals, not wanting to kill innocent people despite being a "bad guy," and clearly deviates from the typical mindset of an evil minion. Still, it's just a normal action shounen type of show where people fight monsters with our Fighter D being in the midst, getting assistance from other boss monsters, fighters, and other spies that want to see the downfall of the Super Sentai monolith.
On the flip side, you have Red, whose painted as a psychopath despite being a hero of justice. While he does kill bad guys and doesn't mind violence at all, he cares more about his image rather than anything else. He definitely doesn't seem to be all that righteous when on screen, but the show doesn't really deign to give much characterization to Red anyhow, so you're going to have to strap on for the second season for that. You also kind of get to explore a lot of other Super Sentai rangers, going from the main cast of the Power Rangers, to the junior ranks that Fighter D intermingles with in his disguised form.
There are definite cringe characters, mainly Yumeko. It's pretty boring to see an OP woman that's flippant and can do basically what she wants under the scrutiny of the Super Sentai organization without much elaboration or reasoning. She's essential to the story, as she's enabling Fighter D to keep his disguise undetected, but it really does seem like the author just wants her to be a facetious OP mysterious female that's evil without much explanation. Overall an extremely shallow persona for such a critical character in the story. She always puts herself above everybody else with her goals never explored.
Overall, I don't mind the story at all, but you will have to understand that it's not a very intellectual one, as Fighter D gets plot armor like crazy to do whatever he wants to do without any trouble. It's a change of pace despite being an action oriented show, but I can't say it's anything special as well.
