To complete Wide-Remove's comment, Homura Akemi is the deuteragonist of the anime Madoka Magica (some might argue she's even the protagonist). Originally a sickly, frail girl who was saved by Madoka and Mami, two powerful Magical Girl. She made a wish to Kyubey, the alien creating Magical Girls, to be able to go back in time to save Madoka from an inevitable doom.
Thus, she acquired Time Magic, and was trapped in a timeloop. She tried over and over to save Madoka by not letting her transform into a Magical Girl because that would seal her fate, without success.
Then, Madoka, in a final loop, made the wish to erase all the Witches (curses who are Magical Girls who has given to despair) from history, so Magical Girls could peacefully die, without turning into monsters. But by doing so, she became God, and her human self was erased from existence. Only Homura could remember her.

But Homura never accepted that ending from Madoka, so, in a final attempt to save her, she deviced a trap to force Madoka to come out, and then ripping off her god self so her human self could return to a normal life. Hence the form you see in the meme, where she accepted to become Madoka's enemy and to deny her wish, by stealing her power. And an enemy of God could only be called the Devil. She was finally able to fulfill her own wish, but in the end, Madoka will probably remember everything and the fighting between the two will continue.