What about Kaname Tosen in Bleach? With his first release command; Cry, he can instantly knock his opponent unconscious. Unsurprisingly, he never uses this ability again. I think that kinda proves he has a story breaker power.
Saiga
05:05:55 AM Apr 24th 2012
Well, the only person he used it on (Uryu) was extremely fatigued and barely standing. Who's to say what it would do to healthier opponent, or someone with higher spirit energy? His Bankai might fit even if his Shikai doesn't, though.
Looks like somebody bulldozed this one and copied the other one over it.
Page history says this happened on November 15th.
Earnest
06:33:30 AM Dec 29th 2010
My bad, I think. I must have been editing Super Power Lottery and this at the same time and somehow mixed them up. The change is reverted now, and I'll port over the new examples added between now and November the SPL.
87.5.132.252
topic
09:15:06 AM Oct 15th 2010
how is accelerator listed as a story-breaker in a verse that is full of guys who make him look normal by comparison? heck, he's not even among the 5 strongest guys/beings in the story, and even if we consider only the humans, he's still far, FAR below Fiamma, and most likely Aleister and possibly even Aurrelus...