How much life loss and gain happens here?

Ok so I have sephiroth, fabled soldier on his front face side, and I have one emblem from him transforming earlier I then have the masamune equipped to him and I have a 1/1 snake and drivnod carnage dominus also on the field. Say I attack with sephiroth and sacrifice the 1/1 snake is it 6 points of loss of life I can spread and I gain 6 life? Or is it something else?