Personality: 

He has a very curious and gentle personality and goes out of his way to resolve any fights around him, even if it results in personal injury to himself (This, however, may stem from the single memory of his mother telling him to "Protect".). He also has a strong sense of obligation, such as the fact that he believes that his mother (and possibly he himself) was at fault for a large incident that occurred which resulted in his only survival, and is therefore responsible for "repenting" in some way. He eventually hardens up as time passes, and even opens up Es to an emotional perspective and he eventually started to develop romantic feelings for Es, who also had the same feelings for him. It's shown that his strong love for Es allows him to subconsciously remember her even after he had his memories erased.