Magus and Robo are directly unified and Lucca acts as their folly personality. The three are most recognizably unified by their catharthis. Robo is some kind of manifestation of Magus's psyche, whether it be by perfect translation of his values to computer algorithm or synchronizing his consciousness into the party post-apocalypse. Magus must have implemented some safeguards to prevent his character from being revealed, in order to manage the possiblility of a time paradox occuring due to the party knowing (Magus is antagonistic early on). Robo and Lucca work cooperatively early on to get Chrono to challenge Lavos.
Let us start by equating Lucca to Prometheus, or Robo. Lucca is the main instigator of the plot due to the onset of various mishaps. This best depicts fire and forbidden knowledge.
Next, I equate Robo to Janus and speculate on Robo's true origins. Robo exists in a world yet-to-be, and an existential paradox is explicitly expressed in the main endings, along with Magus. For those unaware, Janus is a god of gates, passages, time, etc. There traits are best attributed to Robo by the iconic moments as Robo prevents blast doors from sealing and breaks the "rule of three" when the party first meets him. This event is later paralleled by the results of the party's efforts in Magus's lair, where the rule is broken again.
Let's take a deeper look into how Robo and Lucca are depicted. The embodiment of the evolution of their spiritual relationship is legitmazed in the quest for the Green Dream item. Robo labors for centuries (as Magus traversed the void) to create fertility in nature and technology. Lucca achieves this by repairing the fruits of fertility, else we lose our motherhood. This fertility is achieved by a common virtue of reason, and dreaming of desire and ambition.
Let us investigate the primitive singularity portrayed. Chrono, Ayla, and Lucca's house unite as symbols of fertility. Melchoir persuades us from the void to return to a state of prehistory, before conception of evil. This captivating of the red rock manifests itself in Chrono's (our) present, as Lucca's island did not exist in the middle ages (an allegory of Christendom). As the plot progresses, a water vortex allows for easy access to Ayla's rock, and Lucca's home. This is how Magus insidiously gets ready and positioned to access Chrono.
There is also an intermediate level of interference, in the sense that chivalry is dead, maybe Zeal has something to do with it. Frog represents chivalry, and this leads him to desire competition with Magus. Think back to Lucca meeting Frog in the cathedral, a temple of sacriledge. She is explicitly threatened by this amphibian. Frog's character development is one of sufferage, then comraderie and chivalry, and finally moral decay. Magus projects unto Frog his rejection of culture. This hubris is parrodied in the chapters leading to revenge against Magus, "A Hero Appears" and "Tata and the Frog".
Dalton breaks the fourth wall in "A New King". His folly represents the cognitive dissonance of enlightened military personel. This adds further depth to the dilemma of comraderie or chivalry as carried by Frog.
Where does this level of invention lead? Darkness, apocalypse, and vast possibilities. We are all here because we play video games, and they are a novel art form. We are living amongst the first global generations to all be raised using the same art form and able to communicate experience and art universally. This is extremely impactful, and often critisized as a dark moral decay. Video games objectively transcend every other art form by enlisting your sense of sight, sound, touch and feel. You are the silent portagonist Chrono, and Magus and Robo play side-to-side to deliver a powerful message to you. RPGs can be the ultimate empathy training tool if used in proper context. You help decide the ending now.
I would like to detail more commonality between Robo and Magus. Their respective kingdoms represent the spoils of fertility. They both share ownership over symbols of non-communication, isolation, and amnesiac-like dogma. Robo is an empty shell with only a recollection of having positively valued humanity. The eternal kingdom of zeal has an unknown legacy that hails Lavos. The repitition of empty Lavos shells with a party likely containing Magus induces a certain feeling of humor and irony. Finally, I urge the player to freely associate the animations used for Magus and Robo, noting their similiarities.
Like the Rinoa is Ultimecia theory in FF8, this argument often unjustly falls prey to fallacy of equivocation. In a literary sense, the use of archetypes to represent "A" in the argument "R=U if R=A and U=A" is acceptable even when the conscious intent of production was not to unite characters as symbols (which is clearly not the case anyways in CT, as the cast is a clear singularity). Essentially, a combination of the use of time travel and archetypes brings legitmacy to arguments utilizing equivocation.
BTW, I haven't played Chrono Chross yet, so try not to spoil it for me. Might make the discussion a little difficult, but few exceptions please! Please check my profile if you enjoyed this write-up or need more context, as I have similar threads going as of now! Enjoy, kupo!