I was looking through some stuff and I found this:
"Not revenge. It doesn't matter. I-" I stopped short as a fresh circle appeared. The placement, the timing… Legend had been caught.
"Weaver?"
Legend became a blur within the field. Then, in a matter of two or three seconds, the entire space filled with a red light. It slowly became white. Khonsu's power apparently affected all of the space above the bubble, reaching into the stratosphere. It was like a pillar of light.
And:
It was impossible to say exactly how he did it, but Eidolon managed to catch the light before it could turn the battlefield into a smoking rui. It condensed into a ball, swinging around past Eidolon as if he were a planet and it was in orbit, and then flew into Khonsu and Alexandria with a slingshot turn.
It wasn't a long, steady stream like the one in New Delhi had been. It was a white bullet sliding out in a heartbeat, cutting past Khonsu, Alexandria and a good mile of landscape, before driving into the ocean at the horizon's edge. Steam billowed out explosively.
Eidolon crossed the battlefield in a flash, weaving to the left of one of the two remaining columns of altered time, the right of the next, and erected a wall to keep the steam from frying the flesh from our bones.
It couldn't have been precognition that let him move that fast. Enhanced reflexes? Something else entirely?
And he'd been saying his power had been getting weaker.
Khonsu shoots pillars of light that can reach the stratosphere in a timeframe of 2 or 3 seconds. Eidolon manages to react to one such attack.
10 km / 3s = 3333.33333 m / s or Mach 10.061374374. It's possible it didn't reach the stratosphere that fast, though.
This would give Eidolon Hypersonic reactions, and would scale to Scion, Alexandria, Legend, and probably the Endbringers as well.