Jealousy
Jealousy was no stranger to him. He was the very essence of jealousy; envy. He did not wish to be made into existence. It was not his fault he was made with a keening bloodlust, striving to watch humans - those insects - suffer because of him. He was not jealous of them, no, he was Envy. He wasn't supposed to envy anyone. For anything.
But, he was jealous of them. Deep down, Envy the Jealous knew he was jealous of humans. Because, unlike Homunculi, humans had something to live for. They didn't live to watch others suffer for their own gain, or die for no reason - at least, the majority of them didn't.
Humans could have friends, and they could die. Whenever Envy the Jealous got close to someone, which was extremely rare...
They would die right in front of him.
It wasn't his fault.
It wasn't his fault he was jealous.