i know a little about this. Yoshida Shouyo a.k.a Utsuro is the same person actually. Yoshida is the good one and the Utsuro is the evil one wich is the founder of naraku too. In Yoshida Shouyo a.k.a Utsuro body contain a lot of altana ( some sort of energy ) so he has a lot of powers such us regeneration and immortality and another power too.. when his head cut off. the Naraku organization is actually burn his corpse but with his powers he actually come back alive and grew another head from his body and become the evil one (Utsuro). his first head given to his student (i have no idea who it is. could be gintoki, zura, or takasugi, or his another student)
