[When Manabu withdraws Grey lets his arms slip away and fall limp to his sides. He doesn't meet Manabu's gaze, but stares instead at a random point on Manabu's shirt.]

...He used me as a test subject.

[The errand boy was Zelgadis.

Grey takes a shaky breath and elaborates.]

You never heard of Rezo before you got mixed up in all of this, did you? Rezo was known for being a very powerful healer and psychic user. He was also blind, and had been his entire life. His condition was the one thing he couldn't cure, but he wanted to see more than anything. And I was- also blind. And genetically a very close match to Rezo. I was an ideal subject for his chimera experiments.

[Manabu can probably infer a lot from there.]