-When glucose breaks down into ATP, a large amount of the energy is stored as electron on special molecules (the electron carriers). When an empty electron carrier accepts a pair of electrons, it is reduced; when it gives those electrons up later on, it is oxidized.
-NAD+ and FAD; also the two most common electron carriers in the body. NAD+ can accept a pair of electrons (and a hydrogen ion) to become NADH.
hmm ffom what i know, mitsuki is artificialy made by orochimaru hence why we can make multiple mitsuki. and as for kawaki, hes a normal boy who was experimented on by jigen as a possible vessel if im not mistaken