Centurion Squad
A Centurion Squad is a new type of Space Marines Squad available with the release of 6th edition. A Centurion is a warsuit whose STC printout was discovered after the Age of Apostasy. After getting the "not heresy" stamp from the Adeptus Mechanicus, the Imperium of Man began supplying Space Marine Chapters with the suits, who dubbed them "Centurion" after the former officers of the Legiones Astartes. The Centurion is a specialist piece of equipment used for sieges or line-breaking. Despite not interfacing with the Space Marines Black Carapace, it gives the Marine durability that is rivaled by that of a Dreadnought. Instead of recruiting out of the Chapter's First Company Veterans, Centurion pilots are recruited from the Assault or Devastator Squads, as Centurions are only useful in specific roles of Assault and heavy weapons, and their pilots need to be immersed in a specific type of warfare.
They are also commonly referred to as "Space Marine inside a Space Marine" by fa/tg/uys.