Baal

Baaru (バアル) is one of the 72 Demons of the Goetia.

Background
Baal is one of the nine pillars to administrate the spy satellite.

Salomon: The Grand Time Temple
Baal reports that the Eastern terminal nerve were destroyed by enemy Servants.

Baal requested King of Magecraft Solomon to activate his third Noble Phantasm "Ars Almadel Salomonis" against Chaldea and the Heroic Spirits. However Solomon denied Baal's request because he believes the Demon pillars are immortal. Solomon finally convinced Baal to drive away the Heroic Spirits.

Shinjuku Phantom Spirit Incident: Malignant Quarantined Demonic Realm
It turns out that Baal had survived and he had waited 3000 years for the chance for revenge against Ritsuka Fujimaru. Baal allies with James Moriarty against Ritsuka, Artoria Alter and EMIYA Alter.