It's the best taunt lead, fitting your requirements perfectly.
It learn taunt as well as U-turn. It's also effective as a lead due to access to toxic spikes, spikes and useful utility moves such as scald, water shuriken, dark pulse and ice beam.
Try this set:
[email protected] sash
252 Spe, 4 Sp.Def, 252 Atk
Pair this up with a Stealth rock user. Try putting in Spinblockers. Your hazards, if set down perfectly, will cause your opponents much pain.
Air Balloon Heatran pairs really well with Greninja. It also checks Excadrill, who will be OHKOed with Magma Storm, which also breaks its sash. It can then set up Stealth Rocks, and then you can use Toxic spikes. It devastates Ferrothorn too.
Mega Sableye and Mimikyu are good spinblockers, the former being for stall teams and the latter for hyper offence. The toxic damage will slowly wear down the opponent as you stall with Sableye. Again, Ferrothorn, a premier hazard setter, is wrecked by Sableye.
However, beware smart players! Don't rely too much on Greninja. You should try to play with your opponent's mind, and make smart predictions.