What substance do all 3 pathways of the Complement activation lead to

C3 convertase ( C3a and C3b ) C3a is a much more active form compared to C3b which is more of a binding form ( opsonization ). C3b is then converted into C5a/C5b, C5b is then converted into the membrane attack complex. MAC will then insert proteins into the pathogen membrane and cause cell lysis