Eve is a simple minded man. He does not like to think deeply about something and he usually questions about things that he does not have to do. He also appears to be childish in a way, specifically with Adam. Unlike Adam, who is intellectual and calm, Eve couldn't care less about knowledge. Rather, he is interested in anything that's related to physical activity. As long as he is engaged in a physical activity, he is happy. In other words, he is the brute out of the two. Eve also has a low temper, gets angry easily and is emotional. Out of the two, Eve is physically stronger while Adam is smarter. Eve deeply loves and cares about Adam. He is very protective of him and thinks of him as his "everything". The two brothers have a close relationship that it sometimes seems affectionately romantic. Eve always knew from the moment he was born, that he needs to protect Adam. As if he was Adam's shield, because he indeed was technically created to be his shield. He is shown to be extremely loyal to him, paying no attention to what he wants himself and putting his brother's desires or needs over his. As long as Adam is fine with something, Eve is too, even if he hates a decision that Adam made, he does not care or give thoughts about it as long as it makes Adam happy. While Eve is seen as someone who loves playing with Adam in the video game, in the Light Novel, it is revealed that Eve actually does not mind if he does not play at all. He actually decided to suggest playing with his brother because he knew that Adam is interested in humanity. So what Eve usually means when he says "Play" is that he refers to playing what he calls the Human-Make-Believe game, Meaning human activities that Adam is interested in. He knew that Adam likes humanity, so because of that, he usually asks Adam to play with him, because he thinks it makes Adam happy since the "playtime" is related to human activities. As mentioned before, Eve does not care about what he wants as long as Adam is fine with a decision or decides for him. However the only thing that Eve cares about from his own desires is his brother's safety or in other words, not losing him. He usually listens to Adam except when it comes to losing him. When 9s hacked into him, it is shown that Eve finally speaks of what he wants instead of what Adam wants, that is, not losing Adam and that he wants them to be in a quiet place peacefully together. After Adam's death he was overcome by grief that he raged and swore to kill everyone. His loss of Adam caused the machines to go berserk. Eve was also shown to be crying as he was saying "brother" repeatedly before 2B and 9S battled him. He could not live normally after he lost his "everything" that his death felt as if it was a mercy kill. It is important to note that unlike Adam, who thinks Eve and him are the same entity, Eve thinks of them as separate beings.