Arx Angelicum is the Fortress-Monastery of the Blood Angels Space Marine Chapter. It is located on the Blood Angels homeworld of Baal.
The Arx Angelicum was built during the Great Crusade and was capable of housing the entire Blood Angels Legion. When the Blood Angels Legion was reformed as a Chapter and reduced in size following the Second Founding, large portions of the fortress-monastery became disused or abandoned. Over time, these outlying areas of the Arx were buried by the dust storms of Baal until they were ordered unearthed by Dante at the end of M41, both to reinforce the Arx against the imminent invasion of Baal by the tyranids of Hive Fleet Leviathan and to house its defenders - an assembly of the Blood Angels' Successor Chapters. During the Devastation of Baal the Arx Angelicum was almost entirely overrun by the Tyranids and it was here that Dante and the surviving sons of Sanguinius made their final stand in the battle.[2a]
The Arx is built in and around an ancient, extinct volcano with two peaks which lies in the Endless Desert. The caldera of the largest peak was remade into a great wall known as the Arx Murus, which circles the Dome of Angels.
- Arx Murus - outer wall.
- Archangelian - Needle-thin tower upon the Arx Murus that holds the chambers of the Chapter Master[2b]
- Carceri Arcanum - Seat of the Librarius.[2c]
- Citadel Reclusiam - location of the Chapter's Chaplaincy.
- Dome of Angels - Central redoubt
- Heavenward Redoubt - the fortress's keep.
- Sanguis Corpusculum - base of the Sanguinary Priests.
- Tower of Amareo
- Verdis Elysia - farming area where the Blood Angels grow their food.
- Walk of Angels - Open statue-lined path leading to the Dome of Angels[2e]
- Well of Angels[2e]
- 1: Dante (Novel), Chapter One
- 2: The Devastation of Baal (Novel), Chapter Two
- 3: Deus Encarmine (Novel) - The Blood Angels Omnibus, Chapter 8