Sasuke was not at full strenght fighting killerbee .Sasuke just got his MS and just came from a fight against itachi and some other (orichimaru ,dediara),he was not fully rested like he currently is with EMS
Sasuke did how amaterasu but he came to capture killerbee not killed him
Jugo said this is the black flame sasuke was talking about during their fight
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This show sasuke did not want to use it because it might have killed killerbee early and he waited till he transform to use the black flame
sasuke finally decide to use Amaterasu closer to the end of the battle
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this show sasuke wound was not fully heal from itachi battle
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