User blog comment:B214/Volume 23 discussion blog/@comment-87.9.174.130-20170325204325/@comment-29963364-20170330062048

Yeah. But how does a power/ability or item that already exists become a SG at all?

Read Tsubaki Shinra's history on her page. It says that she always had the ability to summon creatures from mirrors. She was even feared and isolated for it. And after she was discovered and reincarnated into a Devil by Sona, her power became her SG, Mirror Alice.

God was dead long before Tsubaki was ever born. So how could her power/ability become a whole new SG from scratch?