My major question is how the pieces fit in the timeline. We have [ counts on his fingers ] 1) Reigen's heart is removed. 2) Reigen's body is left in the garage. 3) Reigen pauses time and writes his letters. 4) Reigen dies. When he wrote his letters, he knew he was going to die. I don't think he was dying by then- his handwriting was steady. So it must be when he saw somebody, knew it was going to be either them or him, and accepted he can't repeat what happened last time.

[ Reigen couldn't have fought back. He just can't see Reigen doing that- the most violence he's seen from that man was his apple attack ]

I can't see the method clearly... It would work if somebody could copy another person's powers... [ eyes Temenos, just in case he's stepping into land mine territory ] Am I right that Axel can only copy one power at a time? Even when he's boosted?