Let's take the starting position with the black royal on e8 and white on e6 and b4. The white move a1 to a8 or h1 to h8 checkmates the royal. Or am I wrong? If not, it took 3 avatars to checkmate the royal.
You don't get the point. There is a difference between forcing mate, and showing that a mate position exists that can be reached if the opponent is so helpful to run into the knife. With a pair of knights there also are many reachable mate positions. (E.g. white: Kb3, Nd2, Ne3; black Ka1; Ne3-c2#) Nevertheless KNNK is a dead draw.
It is quite possible that avatarius plus two avatars can force checkmate. But to show that, one must start from a position like one with white on a1, b1 and b2 and black on e4.
You don't get the point. There is a difference between forcing mate, and showing that a mate position exists that can be reached if the opponent is so helpful to run into the knife. With a pair of knights there also are many reachable mate positions. (E.g. white: Kb3, Nd2, Ne3; black Ka1; Ne3-c2#) Nevertheless KNNK is a dead draw.
It is quite possible that avatarius plus two avatars can force checkmate. But to show that, one must start from a position like one with white on a1, b1 and b2 and black on e4.