The latest Bleach release, chapter 639 ended with Mayuri unleashing a new (repaired?) Bankai that apparently swallowed Pernida.
It might seem like a great victory by the mad scientist especially against an adversary like the Left Arm of the Soul King, but there is always the angle of another surprise opponent unraveling. However, the appearance of Uryu might have been a long shot.
A theory from Reddit user "Kr4d105s2" stated that Mayuri might be betrayed and he has had it a long time coming.
In the fan fiction version, Mayuri has used the Jizou reishi transmution and is now seeing through the eyes of a god. However, at this moment, Nemu stabs him and injects poison in the process.
"Mayuri: This is wonderful...incredible...I see it all, the universe and all its truths and...this power...incredible... My reiatsu....
He is stabbed through the abdomen.
Mayuri: What?! I... No...what is this poison...
Nemu: I'm so...Sorry Mayuri..
Mayuri : I'll kill you Nemu... I am your master...this...is impossible.
Nemu: No...my master is Senjumaru...and to her I served only one order. If you ever broached the subject of the Soul King or his discarded limbs... Then I was to terminate you. (Nemu sheds a single tear.)"
Nemu was a "creation" of Mayuri and he has mistreated her in every possible way but still, her loyalty to Mayuri remained unshakable which begged readers to suspect there must be an ulterior motive.
Mayuri's last words: "That b*tch was right...I felt it... The Soul king's power.and there is no science..... In perfection."
The reference (B*tch) could either be Nemu or Senjumaru.
"Last page: Yhwach sits on his throne smiling as he sleeps.
Editors text - An unwinnable war... The unwavering restful sleep of the perfect being..."
An admission of defeat, that science can never overcome spiritual/mystical power? It may be one of the underlying themes of Bleach itself.
Other predictions were not as dire, as Bleachstates predicted a longer fight that would also involve Nemu, minus the shocking twist.
It states that Nemu, in keeping with the theme of "adaptation and evolution" will gain Ashisogi Jizo and turn the caterpillar banzai into a butterfly. In other words, contrary to the other theory, Mayuri has not won yet, and may not be able to do so without any outside help.
Which theory will hold water? We will continue to cover the best predictions for Bleach until the spoilers come out.