Red Arcueid is a hypothetical version of Arcueid who has permanently fallen to her blood lust to become a Demon Lord. She is manifested through the power of Night of Wallachia, which is able to take rumors and give them form. While the regular Arcueid may be regarded as equivalent to Crimson Moon in this state after having fallen, she is actually a completely different entity, the “materialized form of Arcueid’s overflowing vampiric impulse.” Tatari Arcueid is more similar to Arcueid in this form than Crimson Moon as well.
Red Arcueid mostly resembles her original self, but with a more manic and unhinged appearance. Her hair has become wild and untamed, while her eyes have turned a golden-yellow color, and her sclera have turned blood-red. Her teeth have changed as well, becoming sharp fangs.
Red Arcueid is said to be a hypothetical version of Arcueid Brunestud who has permanently succumb to her bloodlust and has become a Demon Lord.