So 450 guesses/cards to go 🤣

Haha. Thanks for participating as always :D

The Djinn Inferni turns the scavo hireling into scavo firebolt, so might the mystery card be a Scavo Firebolt

Scavo Firebolt isn't the answer but the way you arrived at your guess is really close to how I thought of the riddle.

Evangelist

Sorry, it's still not the answer for last week's card.