Did you watch a early season three guide?

Vel'koz Champion spotlight released today and he is set to come out tomorrow.

is Vel'Koz counter Kha'Zix?

No... he's highly OP though. His ultimate is a pure laser beam for like 3-5 seconds that he can move around with a pretty long reach. All of his abilities are pretty OP so I'd expect a nerf eventually. I think Vel'Koz is just another addition to the void champions. Kassadin, Cho'Gath, Kha'Zix and Vel'Koz.

Ohh,i got it.Vel'Koz is midlane champ i think

He hardly looks op. He looks dangerous, but his ult is very easy to stop and his damage without it looks slightly above average at best. And he seems very squishy overall, and looks very vulnerable to tanky gapclosers.

From the video,i think Vel'Koz counter Zed and Ziggs

Yeah, he's very vulnerable to ganks and such but he has good angles for harassing and as long as he has an allied champion or wall in front of him, his ult can shoot right through those types of things with being interrupted by crowd-control abilities. The zero-cooldown abilities are really nice as well. Maybe OP is stretching it but he is certainly a champion to be reckoned with. Needs more skins too.

No, Zed should win that matchup more than not. His mobility and ability to use the minion wave as defense will make him hard to hit, and he has great assassination capabilities. One instance of somebody doing well in lane on PBE is not enough evidence to support lane counters.

Likewise, Ziggs should do somewhat decently. Ziggs probably has a better trade potential at pre-6, and has a way to stop Vel'Koz's ult, which should let him fight Vel'Koz very well post-6. Combined with better wave clear, and Vel'Koz will be hard pressed to win the lane solely because Ziggs can create map pressure that Vel'Koz can never hope to attain.

I think Diana would also perform well against Vel'Koz because her Cresent Strike and then 2 successive ults of R and high AP will cut through his health pretty quick. Also, every 3rd strike of hers does bonus magic damage along with her already decent AD. She's also deceptively tanky where as Vel isn't.