Drasius wrote:
Thousand Sons Lord on Disk with Seer's Bane.

At initiative Str10 AP2 daemon weapon and you're a T5 jetbike. No saves to speak of (3+/6++ but you can jink), but you're going to double out anything that's not an MC or Nurgle biker.

Save 5 points and make him a sorc for less fluff breakage but 1 less wound and lesser combat stats.

A Tau Commander could do decently with Irridium, 2x guns, Counterfire and VRT since not many people will expect shooting. Going to be difficult to keep him out of combat because everyone will have a bike for the toughness and movement boosts. Alternately, this is the one time a coldstar commander can shine since he becomes a FMC and most other opponents won't be able to shoot him down while he simply flies around raining fire with impunity.

If you want to be hated and break the spirit if not the rules, then an ML3 herald of Tzeentch on disk with Paradox would do it. Summon to your heart's content and pewpew mind bullets with any remaining dice and remain out of LoS forever because jetbike.

A solitaire could also be a nasty surprise if you hide for enough turns to make Blitz really nasty.

If no turn counter, then an Autarch with a jetbike and the relic sniper rilfe should cause a lot of problems for anyone who thinks melee beatsticks are the only true answer.

Dark Angel on bike with shroud of heros and your weapon of choice gains FNP and shrouded which is nice.