(Tireless) Reptillian Juggernaut Udo is a Secret boss encountered randomly during questing in the The Crimson Omen Raid Event. Secret bosses are only encountered after defeating the two end bosses. They are hit for double damage and the player has 2 hours to defeat them. This boss always begins with 21,000,000 hp.
The discoverer of a hidden boss is awarded Rhodonite Key x 12 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 Rhodonite Key x 2.