Looks like from an archboss, because "Roonaldo the Returner" is not from the dungeon.
Those archboss-groups spawn once (or a couple of times, not sure) per day in the area.
As above: Many of the formerly Hardcore exclusive items from Xelorium are now drops from the archbosses.
Roonaldo the Returner drops Pheno-Stem and Breath of Life, and the Bird of Time drops The Eternal and New Ancients' Dagger. The archmonsters are tweaked versions of the dungeon bosses and are easily recognized in the field!
http://methodwakfu.com/en/the-archmonsters/
Instead of
https://www.wakfu.com/en/mmorpg/encyclopedia/weapons-shields/22361-breath-life (-> 404)
change to
https://www.wakfu.com/en/mmorpg/encyclopedia/weapons/22361-breath-life
Looks like from an archboss, because "Roonaldo the Returner" is not from the dungeon.
Those archboss-groups spawn once (or a couple of times, not sure) per day in the area.
Roonaldo the Returner drops Pheno-Stem and Breath of Life, and the Bird of Time drops The Eternal and New Ancients' Dagger. The archmonsters are tweaked versions of the dungeon bosses and are easily recognized in the field!