LPOV
Lucifer knew that it wasn't Alastor's fault, he never would have killed Charlie on purpose, he loved her like his own child. He didn't blame Alastor, he blamed himself, it was all his fault. He should be in grief, in tears, mourning, sobbing, and screaming. But he wasn't. This had happened too much to him, every time he got comfortable with life, when things were going well for him, something like this would happen. Something so heart-wrenchingly terrible, something that heaven thought was sure to break him. However, he had grown accustomed, accustomed to the way of hell, the place he had condemned himself to. All of this was his fault, all of this he deserved.
Not Alastor though, Alastor didn't deserve this, he may be a sadistic murderer on the outside, but he was the kindest soul that he had ever met. Except for Charlie, but now she was gone, and he had to deal with it.
He looks back to Alastor, letting his arms drop from around him, they hang uselessly at his sides. His glowing yellow eyes meet Alastor's shining crimson ones, they were truly beautiful however nothing in comparison to the rest of his beautiful darling. He would mourn later, now he had Alastor to attend to. Alastor, so young, so innocent. No, he would need help or else he would break.
Wouldn't it be kinder to put him out of this miserable world?
Alas, Lucifer's selfishness won over his righteousness, and he leaned in for a kiss.