These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Designated Villain: The only reason Kai is a villain in the remake at all is because he's the only one around to take the spot of the Big Bad, which isn't so off since he started out being the Big Bad in the original fic, only to be revealed to just be a dragon.
The funny thing is, no one paints him as a villain, it's just him who constantly claims to be a villain. He's not off though, he did at one point seem like he wanted to kill Lee. Except Lee survive, though if it's not known if it's either Lee being Made of Iron or Kai holding back.
Ensemble Darkhorse: Ryuuji's a parody of one, but that doesn't seem to stop him from being one to the author at the very least. Ryuuji's starred in two spinoffs so far and Ryuuji unlike the other characters, didn't get Out of Focus that much in the original fic. He even makes an appearance at the very beginning of the remake! Although said appearance is a Tear Jerker flashback. Heck, he might be one to the readers of Redryuranger11 fics since there might be no one who has not heard of Ryuuji Hinote.
Rai appears a lot in other fics by the author. Most notably in Kurayami Sentai Kageranger in which he serves as a 'rival' to one of the characters, and Radiant Sentai Seinaranger, in which he gets into a fight with The Hero. He's also the love interest to whom seems like the main female in that story. He's also the star of Uncle Gaoranger.
In reality, KODENBLACK. Seriously, for whatever reason, there are messages talking about Kodenblack to the author asking just about this ranger. One guy even asked if he could merge Kodenblack with Kai as a character for a Power Rangers fic that he wanted to write. The author declined.