The trick seems to be that you need to bring each one back to Tirso before you kill your next boss, so it's best to return to Albero to turn a herb in before you carry on, even if it is a bit annoying back tracking.
Mountains of the Endless Dusk: coming from the Brotherhood of the Silent Sorrow, on the left, exit the area with the Prie Dieu and it's in this area Patio of the Silent Steps: in the second to last "room" Blasphemous is a beautifully crafted Soulslike/Metroidvania action game set in a delightfully unhinged, deliriously gory world filled with well-designed enemies, satisfyingly meaty. First thing’s first, when you see a circle appear on. For this boss fight, we’d recommend using some defence and attack boosting equipment. Exposito, Scion of Abjuration is one of the later boss fights, and it sure isn’t easy. Sleeping Canvasses: in the tall room with the ladder in the middle and the 3 possessed paintings Blasphemous is a tough game, so it’s not surprising that the boss battles are tough too. Where Olive Trees Wither: go into the area after Gemino, and all the way across to the left hand side of the area, at the bottom left go through the opening and it's in there Jondo: at the very bottom right room of the area Albero: but you need to find a teleporter in a different area and teleport back to Albero (the room it's in unlocks from the inside), the item is in the teleporter room
For his quest you need to bring him 6 healing herbs. He's the guy on the level you start on when you run into the main building.