I think all the people who believe Amakusa is Erika´s ex can now see it´s wrong.
They have clearly the wrong eye colors. Besides if he were the timeline with Erika and Ange wouldn´t match up. Amakusa was Ange´s bodyguard after the tragedy of 1986. So at that time he was at least I would say 20+. Eva would only take bodyguards who have got hard training and are skillful not some young school boy I believe. But Erika´s ex is way younger still being in high school with her. 1986 Erika was 16-17 years old as we know. Around Jessica´s age. So this makes a big time glitch.