Thanx to iq40 , I now know this is Kamen Rider Leangle from Kamen Rider Blade. In the show, he's supposed to be the strongest rider but his alter ego, Mutsuki Kamijou is actually a very weak-willed person (at the beginning). The Ace card that gave him the power to "henshin" (transform) always used this weakness to possess him and try to destroy the other riders.
Thanx to Evaritus Lau , I now know this is Kamen Rider Kabuto, The Bee.
I found these figurines discarded opposite my block and so I brought them home as toys for my kids. After cleaning and disinfection, the figurines still look pretty decent despite their missing weapons. I'm out of touch on Power Rangers having only watched the very first with English casts. As for Kamen Riders, I'm totally out of league! Maybe you guys could enlighten me on these characters' background? Thanx in advance!