>>714336137
Not Gaster.

At this point I'm thinking the person on the phone had to be The Knight or FRIEND. With both of them fully working together on this whole Shadow Crystal thing.
It makes no sense for Gaster to be going to Jevil and gassing up the Knight or giving Spamton business advice till he signed a contract with someone else. But it'd fit perfectly with FRIEND doing that stuff in "service" to the Knight with them both planning to fuck over Gaster's whole system on the side by pushing the heroes towards FREEDOM.

Y'know, it's kinda funny how we were so set before on the secret bosses being caused directly by Gaster, an entity that hasn't even been named in the game thus far. Something that the average player would never really get without delving into the history/code.

The Knight being behind it all is such a simpler answer. It's our antagonist bound to the Prophecy the same way we are. It is making the secret boss stuff in each Dark World so we can have a shot at breaking the prophecy through the power it lends us with the Shadow Crystals.