One of Doctor West's creations, Elsa is a gynoid, built to be stronger and faster than an ordinary human, equipped with a pair of tonfas. Although she recognizes Kurou as her enemy, following an encounter where he saves her, Elsa admits her love to Kurou, much to his confusion. She ends most of her sentences with the suffix "robo".
Elsa's name is probably derived from Elsa Sullivan Lanchester, the star of the movie Bride of Frankenstein.

source: Wikipedia