My character on the “Absolute” difficulty of Tomb of Archon Barthollem is missing the boss Malkadarr, Champion of Death’s Vigil on the second level. Reputation with the Chosen of Kymon is maximum, with the Order of Death’s Vigil “sworn enemy”.
Have you accepted the quest to “Gather the Sacred Ashes” yet? Malkadarr will not appear before taking on this quest.
That’s the quest you get after killing Master Ravok, but not from Brother Ellivius but Brother Miranok who is in another room.
Of course, I did all the quests of Kimon’s chosen ones and the story quests. It was a bug of one character, I created a new one, reached the episode after completing the task you indicated and killed the mob I needed.