"...If fate is a millstone, then we are the grist. There is nothing we can do. So I wish for strength. If I cannot protect them from the wheel, then give me a strong blade, and enough strength... to shatter fate."
Saigo no Getsuga Tenshō (最後の月牙天衝, The Final Moon Fang Heaven-Piercer) .
Mugetsu (無月, Moonless Sky): Generating a blade of deep black Reiatsu in his hand, Ichigo swings it towards his target. Doing so causes a massive veil of black Reiatsu to erupt upwards and approach the target, darkening the sky and heavily damaging anything caught within the blast.Afterwards, the energy continues to rise before dissipating into the sky.The technique is strong enough to severely damage Sōsuke Aizenin his strongest evolutionary stage and force him to regenerate at a previous stage.