By picking a Single Boss target at any setting you will get the name of the boss you need to kill in the adventure window. Just attribute the name to the layout to the rare and cycle through the adventures until you get the one you need.

-The Aisles of Blood: Crypt Watcher, Lady Tsaellia, Sivli Starsiren
-The Asylum of Invoked Stone: Prince Aviatis, Kuren K'sayen, The Keeper of Flesh
-The Cesspits of Putrescence: Bial the Blade, The Widow, Midwife M'seri
-The Chambers of Eternal Affliction: Grandsteward M'rakish, The Keeper of Blood, Numelou the Learned
-The Dreary Grotto: Master Larithim, Warlord Thavrin, Sepren the Lost
-The Forlorn Cavern: Ulyist Son of Night, Khestin the Bold, Fesset the Leech
-The Halls of Sanguinary Rites: Baelthorn Born of Blood, Hhovris, Fleshspinner
-The Infernal Sanctuary: Eclipse, Huketsa the Ageless, Oneblood
-The Ritualistic Summoning Ground: Avedranna, Empress Atiache, Dierdri the Raven
-The Sepulcher of the Damned: Keeper of Breath, Yavrin,, Harvestmaster Viestri

With the important caveat that, when requesting a dungeon, any of the last 5 dungeons that you have started will not be included in the possible dungeons you request next.

Questions? Comments? Post them here! Original page - https://achievements.eqresource.com/achievements.php?id=700053