A former government agent, Kateri Deseronto had her clearance revoked due to mental instability following the death of her son. Blaming Spider-Man and the Hobgoblin, Deseronto broke into the facility she worked in and stole a state-of-the-art armored suit and became the vigilante Coldheart. She later confronted both Spider-Man and Hobgoblin but found she was unable to kill Spider-Man after she had seen him save an innocent child from falling off a building.
Coldheart wears a state-of-the-art armored costume whose full abilities are unknown. She wields twin swords capable of producing an energy that paralyses with a touch of the blade, or can be projected to freeze objects instantly . Coldheart is a highly skilled martial artist and swordswoman.