IMO he did. 1) He wanted and needed to get into the most horrifying fights, to get that extra boost for his powers. 2) Scion: "You needed a worthy opponent". 3) After he dies, the Endbringers are no longer hostile. Basically, robots waiting for orders.
Regarding 1). His powers are already not entirely under his control. They will give him the capabilities he 'needs', rather than the ones he 'wants'. Now, if you take his subconscious, which is more or less "I need someone to really lay into" 24/7 and then link it to a shard which is (like every shard) combat-oriented, with the sheer breadth of powers available to him, is it any surprise he made three monsters. The first he formed in the centre of the earth, the second at the bottom of the ocean, and the third on the far side of the moon. These lasted some time, until Scion killed Behemoth (after the hobo told him to, which was perhaps not the wisest thing in the world to do). Then his subconscious goes, wait a second, I don't have the scary one to fight anymore. So it conspired with his shard to make even scarier ones.
Note that Behemoth was all about brute power and killing shit. Pick a target, go for it, kill it. Kill some capes inside a certain radius. Energy is diverted or reused. A very hard target, in other words.
But he wasn't scary enough. Had no tricks that could really hurt Eidolon.
So Leviathan was born. Leviathan sank landmasses. He was also tricky, had the hydrokinesis, and brought on the urgency of tidal waves pounding the coast while you were fighting him. He was also much faster and in-your-face than Behemoth.
But he wasn't scary enough either. A tricky brute wasn't quite enough.
So Simurgh was born. All about the mind. Anyone staying too near had to worry about mental corruption. This brought an urgency into the matter. Also, later, pulled up pseudo-Tinker tricks from the mind of anyone within range. Far trickier than Leviathan, could set up domino-effects in human brains to trigger far down the track (as shown with the Travellers; Krouse was reminded over and over of his love for Noelle, and Noelle was manipulated into drinking half the formula. Cody was set at odds with Krouse, and thus later killed Accord at the height of the battle with Behemoth ...).
Which came full circle, as the Eidolon clone denounced the Protectorate during the Echidna fight.