I'll Make the Cold-Blooded Margrave Melt With My Fire Magic

https://www.cmoa.jp/title/316783
Selene, a noble lady born into the prestigious Northwind family, has inherited the family’s revered power to control fire—a gift that has led their bloodline to be worshipped as messengers of the gods. Yet despite her heritage, she spends her days living in the shadow of her exceptionally talented younger sister, neglected and mistreated by her own family.
One day, Selene is presented with a marriage proposal.
Her prospective groom is Elliot, the lord who governs a frigid borderland plagued by constant warfare and feared as the “Cold-Blooded Frontier Count.”
Preparing herself for a harsh and unforgiving life, Selene travels to the snow-swept frozen frontier.
But in that land of relentless blizzards, the extreme cold unexpectedly awakens the true potential of her fire magic…!?
A love so passionate it can melt even an ice castle!
A heartwarming romance between two awkward souls whose devotion grows hotter and sweeter with every passing day.