Why Leo and Seija are so easily comparable

(Leo as in one of the main antagonists of Fire Emblem Fates Birthright, Seija as in the main antagonist of Double Dealing Character)


 * Both get on my nerves in one sense and are kind of likeable in another.
 * Both have ideas that go against the protagonists' (Leo calls Corrin a traitor nonstop, while Seija wants to overthrow society so that the weak rule the strong (a bad thing for Reimu/Marisa/Sakuya, because they're among the strong ones)).
 * Both try to manipulate another antagonist (Camilla in Leo's case, Sukuna in Seija's case) and succeed.
 * Both have access to powerful magic (Brynhildr in Leo's case, flipping the screen in Seija's case).
 * Both wear black (or at least SOME black).