The Desmodus is passively tamed by placing blood packs in the final hotbar slot and allowing it to pick you up and feed, with parachutes recommended in case it drops you. This versatile flyer can cling to surfaces, navigate caves, use echolocation, turn invisible at night, harvest blood, gather spoiled meat, heal by feeding, and support taming and imprinting with its Sanguine Elixir. When encountering one, use ranged weapons and avoid cliffs or hazardous terrain, while taking extra care in caves where groups can overwhelm you. A tamed Desmodus is also a formidable combat mount that can recover health using blood packs.