The Master always comes back.
Anybody claiming Missy was the last doesn’t understand how it works.
1st Master literally died. The actor.
So they brought him back as a crispy critter, last regeneration, dead, no more.
Found a way to cheat death. ALWAYS finds a way to cheat death.
I remember when the Master was CREMATED – cremated – ASHES TO ASHES, dust to dust, no more. Totally completely just GONE.
And after that, you believe it. You ALWAYS believe it. IT’s finally the end. They killed off the Master… forever.
Then some time in the future, what’s this? How’s the Master back? we saw Master BURN! And yeah his ring was left behind but…
oh damn it… the RING…