Well it is true that Anna and Elly are similar in some aspects they are also very different.
Sure, they both have red hair, but where as Anna's is by chance, Elly's was inevitable. Something she could never shake because of what it identified and embodied. The blood stained history of humans fighting against opression and slavery in the name of Freedom and Independence.
And where as Anna would do anything to stop the apocolyps. Including sacrifice the lives of two men who did nothing but good for the world Elly would never concider it, she'd feel that it was a loss either way if it happened that way, not that Elly blames Anna. She understands her reasoning but that didnt mean she thought her plan was just.
And Anna fell, as did Elly. But if you were the angel of Freedom and Independence you probably would have done the same. Elly had always wanted the free will humans possessed, all the way back to ancient Athens when she'd watch their Greater Panathenaea Festival for the first time.
She had stayed however. Not wanting to abandon her metor and idol Anael, or her best friend whom she was hopessly in love with but was afraid to admit it, not wanting the other angels to know because she knew they'd see it as weakness and a flaw, all except Anael who understood because she was the angel of love after all and she knew that it could make you stronger then any blind faith.
Then Anael had fallen and been given the name 'Anna Milton' by her human family, she had watched her for a year or two as she desperately tried to convinced Samandriel. She hadn't wanted to leave him behind, knowing that it would break the promise she had made nearly 2,000 years ago when she told him she'd always be there for him.
In the end Elly had realized it was futile, and that Samadriel just didn't see the fact that Heaven was opressing their thoughts and desires and she had hovered in the sky that day, looking down at the people of the 20th century letting tears flow for the first time since she was a child and her older brother Zachariah had berated her and called her a 'Snivling excuse for a Seraph' because of what she represented. Anael had come to her defense and when Zachariah had let she told her not to show people tears when they treated her like, that it just gave them satisfaction and encuraged them. So she had always held her tears in from then on, only showing positive emotions if any.
She didn't know it but Elly had been waiting for that one last time she would hear it. She had wanted to hear Samandriel say her name one more time knowing that once she did this she might never see him again. And then she had fallen, plumited to Earth faster then she thought was possible, she had screamed, not just in agony of her grace ripping out but of lost love as well
You see, just because people are similar doesn't mean their the same. Its little differences that make up who a person is and make them unique, not their similarity's. That's why I get so upset when people tell me I've just copied Anna in making Elly. Just because Elly is a fallen angel with red hair doesn't mean I copied Anna, I dont think any being can ever be a copy of another. Even fictional characters, there will always be those differences that set them apart, wither they be big or small.