Seeing Kanae in such a state had made Eden's heart turn cold toward those who made his little guy suffer. He wanted to kill them right here and now. But unfortunately, he couldn't. First, because he will surely be taken down by Rose the moment he will try to kill Liam, and second because he was simply not strong enough.
And even though he was blaming them, he was blaming himself a lot more.
It was his fault if Kanae was in such a state. His wings even darken so much because he was constantly healing himself from the injuries he was suffering.
But it was actually when Kanae told him that he was sorry that it made him feel bad.
The first words of someone were usually full of happiness. But Kanae's were instead full of sadness. He had apologized to him. Not because he couldn't do anything, but because the fact that people had seen his wings would bring problems to Eden.