Manga volume 5
Chapter 29
Sho and Mizuki witness the blast. They then see Gyuo standing where their friends were. They run. They are chased by zoanoids but are saved by what looks like guyver 3.
Chapter 30
They hide in a cave and discuss why Sho cannot transform. Mizuki mentions his dad and then that upsets Sho quite a bit. It seems he has been blocking it. Guyver 3 arrives. It is actually Aptom!! Aptom kindly tells Sho that he killed his own dad.
Chapter 31
Then Aptom grabs hold of Mizuki and turns into enzyme 2! Sho tries and tries to turn into guyver. It is only when Aptom has shredded all of Mizukis clothes (yes she is naked!) that he finally manages to change. (I think it was his subconscious mind wanting to see Mizukis privates!) He transforms and kicks Aptom in the chops.
Chapter 32
Aptom then demonstrates how he can change into many different type of zoanoid. He can even mix them together. Aptom proves a very tough opponent but Sho eventually hits him with the mega smasher. All that is left is one arm.
Unfortunately Aptom has acquired the unusual ability of regenerating himself. The arm changes into a torso and Aptom crawls off.
Chapter 33
Sho returns to Mizuki (which is actually quite a way back). The hyper zoanoid team 4 (Thancrus was killed by guyver3 while Sho was fighting his dad) arrive at the scene of the battle. Aptom drops down from above and grabs Elegen. He takes over Elegens body. He then escapes.
Chapter 34
Guyver is on the run. He runs through the streets of a town.
He tries not to kill the zoanoid because they are all innocent people that have been changed. They are cornered and they will take him prisoner or he can kill all the innocents. They all get cut up by Guyver3! It is the real guyver3.
He explains that once you are a zoanoid there is no going back. Also he tells them that everyone is safe under the Chronos base in mount Minakami!