Rachele, Rime Warden is a secret boss encountered randomly during questing in the Skies of Fire raid event. Secret bosses are only encountered after defeating the two end bosses and the two hidden bosses at least once each. Secret bosses also don't show up until after half time. They are hit for double damage and the player has 2 hours to defeat them. This boss always begins with 18,000,000 hp.
The discoverer of this secret boss is awarded max 10 Bronze Keys if the boss is defeated. Additionally, the discoverer and anybody else who participates in the battle and does at least 1,000,000 damage to the boss is rewarded with 2 Bronze Keys.
Quotes: "I will freeze your very soul!"