Champions
From UO-Phoenix Wikipedia
Champion spawns are difficult encounters designed for groups of players to obtain powerful items designed to challenged skilled late game players. These encounters can be increasingly difficult with different mechanics designed for groups of 4+ players taking an 1-2 hours to complete to obtain power scrolls to advance character development and also obtain replica equipment and unique decoration rewards. Each champion has 1 dedicated location and or can spawn randomly from the random spawn locations aside from the Harrower and Khal Ankur which are special boss champions and have unique spawning requirements.