ok, so, lets SUPPOSE ~~
P.S - Its pure imagination stuff,
fugaku uchiha have 3 kids , say
Itachi (older), Shisui (younger) , Sasuke (youngest)
Ok, so they all awaken MS.
Now, Sasuke Give his MS to Shisui, for some reason.
Shisui awakens EMS, ok.
So, shisui awakens EMS and gives it to...