Metamorphis from Gandahar (The English version of the movie is called Light Years) 1987.
This is a French animated film that features a planet called Gandahar that has been colonized by humans who have created a near-utopia using bioengineering technology. One day, black, statuesque robots start invading and petrifying portions of the populace and carry them off somewhere. Nobody on Gandahar knows where they came from or why, but fingers started being pointed at a giant brain in the middle of one of the planet's oceans known as Metamorphis.
Metamorphis had been leftover from a prior experiment of the Gandaharians a long time ago. It was presumably an attempt to create a giant biocomputer. However the experiment was deemed a failure as the brain did not seem intelligent at first but it kept growing in size. So, the Gandaharians at the time abandoned it on an ocean platform and forgot about it.
Metamorphis seems very cryptic and puzzled at first when asked by the protagonist as to where the metal men came from other than deducing he had some sort of connection to them but not knowing how or why. He sends off the protagonist who would later encounter him again in the distant future as Metamorphis wants the protagonist to kill his future self as Metamorphis is not yet a villain.
Then in the distant future, the link between Metamorphis and the metal men becomes clear. Metamorphis himself has become sickly and senile with age and violently lashes out at the protagonist not recognizing him from the past.
It is a great example of how a villain does not necessarily start out as one as characters change over time.
