Wait a second... didn't Danzou say that in order to use Izanagi you had to have power from both Uchiha and Senju?Ok so? He has a shit load of sharingan he lost the eye from izanagi
Not to be mean but...NAW YOU THINK U JUST NOW KNOWING HE HAD THE FIRST CELLS IN HIM WTF.Wait a second... didn't Danzou say that in order to use Izanagi you had to have power from both Uchiha and Senju?
If that's the case, then Obito's self healing arm in the latest chapter and his recovery are most likely the cause of being injected with the first Hokage's DNA