Could it really be her…?
DABL-JP011 赫の聖女カルテシア Aka no Seijo Cartesia (Cartesia, the Holy Red) / Red Cartesia, the Virtuous
Level 4 LIGHT Spellcaster Tuner Effect Monster
You can only use the 1st, 2nd, and 3rd effect of this card’s name once per turn.
(1) If you have “Fallen of Albaz” on your field or in your Graveyard: You can Special Summon this card from your hand.
(2) During the Main Phase (Quick Effect): You can Fusion Summon 1 Level 8 or higher Fusion Monster from your Extra Deck, using monsters from your hand or field as Fusion Material.
(3) During the End Phase, if a Fusion Monster(s) was sent to your Graveyard this turn: You can add this card from your Graveyard to your hand.
赫 is the same kanji used for “Branded in Red” and “Masquerade the Blazing Dragon”
聖女 is the same Kanji (Holy Maiden/Female Saint) as “Dogmatika Ecclesia, the Virtuous” and “Incredible Ecclesia, the Virtuous”, as well as “Condemend Maiden” and “St. Jeanne”
カルテシア seems to play on Renatus Cartesius, the Latinized name of René Descartes, the famous philosopher best known for “Cogito, Ergo Sum” (I think so I am) and is one of the founders of modern philosophy. He was also the creator of analytic geometry, an area of mathematics that linked algebra to geometry proper. Also, its name comes from “The outskirts of the city” (Des Quartes) but it can also be taken in Latin as “What is thrown away”
Also, of note, given her synergy with Despia, she’s probably referring to “Cartesian theater“.