Twelve-Winged Dark Seraphim
That's a pretty big piece of plot you had left out, you know that right, author? Because, you know, enemy of mankind, stronger than evolvers by several ranks, *psst* not big deal at all, right? Oh, and apparently aliens wield katana as well! How strange! How original! And the fact that their images and names are based on a certain type of demon from the East is very strange as well, because, you know, apparently humanoid is the ideal type of physical body in base, not some weird shapes like a glob of muscles, tentacles or arachnid-like. Oh, and let me guess, their power is totally not of dark elements or shadow-related, right?