so that leaves one more right arm right? since nachete killed the Blood copy?

I guess so..but I'm confused about the left arms.
One left arm in tanned skinned boy's body..another one in High Priest Eigi's body. Then how about the last one? in Amace's body?

I don't think Amace has an arm in him. he's more possessed to get the Blood and Isucha from his pervious mission in the very beginning that he failed at.