You've defeated 250 cold demons, making you Coldblooded.
How to Get
Defeat 250 Circle of Thorns cold demons, including Hordlings and Hellfrosts.
Gladiator Badge Unlocked
When you obtain this badge, you will unlock the Hellfrost Gladiator badge.
This is the hero version of the Coldhearted Badge. This badge is normally a Villain only badge, but during the Valentine's Day Event 2006, Valentine's Day Event 2007, and Valentine's Day Event 2008, where heroes and villains could team up against the Circle of Thorns, it became possible for heroes to accompany villains on missions that would spawn the necessary enemies for this badge, allowing heroes to earn the badge. Currently this badge cannot be earned by heroes via any other method.