Caliborn calls Lil' Cal a "juju." Later, Calliope explains that "juju" are said to have origins impossible to trace, emerging out of the void, and cannot truly be copied or destroyed Lil' Cal is a fine example of this. He was created by Gamzee as a nightmare to haunt Dave's dreamself based on Bro's puppet. That nightmare eventually was sent through a Skaian portal to become Bro's puppet, and then that puppet through elaborate shenanigans ended up following Jack into the

the troll’s session and eventually wound up in Gamzee’s hands, inspiring his own creation. It gets even more complicated: Gamzee’s creation is not entirely of his own volition; Dirk’s Dream Cal is found by Gamzee and given to Caliborn, and after Caliborn stores his soul inside Dirk’s Dream Cal, it becomes, in Caliborn’s words, “ENTANGLED WITH THE VOID” and is then transferred by Gamzee into the Cal he “creates.” As a result, Lord English is created, and he inspires Gamzee’s “chucklevoodoo” abilities and, with help from Kurloz, ensures he travels far enough in the void to get to Caliborn. Without Gamzee, Caliborn would have never discovered Cal. 

Caliborn does channel his Soul through Lil Cal but you’re also forgetting that it becomes possessed fully, not when he stares into it, but rather when he gets sucked into it after the Masterpiece.

I mean this entire sequence isn’t even that hard to follow, since we have a flash dedicated, precisely, to Cal’s entire Timeline.