Here's an idea, perhaps Apollon is an Avatar for Archenphel and the suit is a high powered armor used as a disguise. Archenphel doesn't know Aptom, and even if Archenphel did know about Aptom, he would never be able to recognize him in his battle form. Archenphel saw Aptom in his human form. It makes some sense to me since Archenphel is too physically weak to roam around the world and solve Chronos's problems, but has the power to defeat any of the zoalords. The motive could be, in light of Guyot's rebellion, Archenphel may have accepted that then humans gifted with the zoacrystals were no longer trustworthy and were able to rebel against archenphel's orders. Not wanting to take the chances of having other zoalords follow in Guyot's footsteps, Archenphel used Imakarum, whom Barcus had admitted to giving special processing for Archenphel, to take back the zoacrystals for whatever means Archenphel wants them for. (Perhaps to power the Ark?) Knowing Imakarum may not have the power to take back all of the crystals, Archenphel uses Imakarum's body as his own and handles this affair himself; just not literally himself.
Confirmed, Plausible, or Busted?