Tetsuhito Kagiroi [Tenjou Tenge]
With the mohawk and buff figure arises an air of toughness and arrogance, albeit it's a controlled arrogance that belies the man’s true nature. On first appearance you don’t get the feeling that he is actively trying to appear intimidating as regular manga thugs would do. However as his air of civility eventually fades away, the design allows him to successfully transition into a monster. Also that blade of his looks hardcore.
Killy [Blame!]
Whilst I didn’t quite like Nihei’s art for the first quarter or so of Blame! due to the characters being awkwardly proportioned at times and Killy’s grass-like hair(The environment was top-notch through-out though). There were vast improvements as the manga went on. Killy for the second half of Blame! looks like a man of no compromise, a very badass one at that. There’s a ruggedness in his youthful facial feaures, which combined with the suit and handgun sized GBE gives sense of professionalism and total efficiency.
Grimmjow Jeagerjaques [Bleach]
Like Tetsuhito, a fine physical specimen. However rather than that misleading sense of controlled arrogance, the messy blue hair, scarred chest, six-pack and that crazy grin all suggests the opposite. The Sexta Espada does not care to hide his ferocity, his resurrection further accentuates this. Its streamline design, wild long hair, talons and tails are predatory characteristics that literally bring out the animal within him.
V.V [Code Geass]
Androgynous. His eyes got that same Selim Bradley look of coldness which suggest a disregard for human lives. Though unlike the latter whose appearance is designed to blend in as an ordinary child, the royal clothing and body length+ blonde hair only adds to the air of loftiness, emphasing that he is no mere mortal.
Ichimaru Gin [Bleach]
He does genuinely look like he’s enjoying himself almost all the time, though I never thought the smile to be creepy tbh, slightly mischevous perhaps. It effectively combines with those large long sleeves to be suggestive of his mysterious psychology and agenda. Though the best part actually comes when the smile drops and the eyes open. That one backward glance at Hitsugaya would have you well reminded that his limit is not to be tested.
Saito Hajime [Rurouni Kenshin]
He’s got that villainous look going on, the eyes and facial structure radiates killer intent and the same predatory instinct that Grimmjow would be proud of. Though Saito looks far more experienced and cunning. Like with Killy the police uniform also suggests military efficiency, more importantly it reflects his sense of duty as an adherer of Aku Soku Zan.
Donquixote Doflamingo [One Piece]
Flamboyant clothing + bare chest + sun glasses and all that tongue poking gives an impression of a slightly loopy hedonist.
The teddy bear guy from Afro Samurai, can’t remember his name, but the mask has got that built-in cool factor.