Livre Ex Machina in Bloodstained: Ritual of the Night will lead you back into the castle from the Tower of Twin Dragons area. There’s a very useful ability to collect here, as well as an NPC to talk to.
Below, we’ve included a complete map of Livre Ex Machina with a few notes about the area.
Livre Ex Machina map
Your first visit to Livre Ex Machina will come through Tower of Twin Dragons. You’ll have to fight Andrealphus and collect the Double Jump Shard ability. You’ll also meet Orlok Dracule, the vampiric librarian.
After you defeat Bathin in the Underground Sorcery Lab, return to Livre Ex Machina with the Reflector Ray Shard ability to continue upward. Toward the top, you’ll have to defeat Abyssal Guardian — a large dragon — to continue through to the Hall of Termination.