Is he Kabuto and Karin cannot recognize his new augmented chakra? I don't think so, it would still have some familiarity to it. Is it an Edo Tensei? I think it is, crackly barefoot man could the So6P but that would be over the top. Personally and I have no basis for this belief, it is Izuna. The only major character that has not made an appearance. But who would be the Edo Tensei caster? I don't know..