Okay, at first I didn't really like this series as it seemed to drag along at a very slow development rate, but after the introduction of the 4 Dragon Forms, it started to get interesting. I love how its going to the point that, the more magic and power that Haruto draws out from himself and his inner Phantom, 'Dragon', the closer he comes to possibly destroying his old self and becoming a Phantom in the process.
Medusa is just a complete b***h but that's why I like her so much. She has so much potential and it seems that she will probably play a bigger role as time goes on.
Wiseman, this guy just creeps me out. I actually think he might have some connection to the White Mage but that's just my speculation.
Gremlin is a nice character and it's cool to see a villain who sneeks around and uses both sides to his own advantage. Haven't seen that done properly in Kamen RIder for a good while.
Phoenix, I LOVE THIS GUY! Arrogant and a pure badass. And his Phantom form is really well designed.
Kosuke Nitou / Beast - Now this is a Rider form that I love. Haven't seen a Rider form for a secondary Rider this nice since...well...Kabuto. Tasuku Nagase, who plays Kosuke, does the character very well though I really don't get his extreme love for mayonaise. A really well designed Rider and fun to watch.
The other characters we already know a lot about but these are some of the ones I've not seen talked about much by those that I talk to about Kamen Rider. So far, the series is now starting to impress me and I find it much more enjoyable than Fourze. Sure, Wizard has its ups and downs, the suit design of Wizard still being somewhat...well, not to my liking. But I'm getting used to it and the flow of the story.