Although he was corrupted by the Mark, God said it just made him "more of what [he] already [was]". In other words, it simply brought out the worst in him. However, his worst is not like other angels', or even other monsters'.

He crushed a woman's skull and said he liked how warm and wet it was. He tortured Sam to the point he went insane just to pass the time, something not even Dean went through, even though his torture was necessary to free Lucifer in the first place. Castiel said Sam's soul felt like it had been "skinned alive" from the torture it had endured.

On the other hand, from his PoV, he was betrayed, time and time again, blamed for everything that ever went wrong, and all he wanted to do was to make God proud, albeit in his own twisted way. He didn't want to kill Michael, and even offered him a chance to "walk off the chessboard". He mourned for Gabriel's "death", and so on.

Is Lucifer the product of his circumstances; a tragic figure? Or did he "come out of the production line" like this? What do you think?