adeptus_mechanicus
Subfaction Warhammer_40,000: they are a religious cult that venerate the Machine God as supreme being and consider the machine as the most perfect form attainable by the mankind.
Members always have mechanical_augmentations (many times so heavy that they could be easily mistaken for robots). Usually their members wear red cloaks with a hood; in many depictions they could wear other types of robes, but always coloured of red (their holy planet is Mars, the Red Planet).
Their emblema is a skull half human and half robotic.
Prior to Horus Heresy at millennium 31 were known as cult mechanicum.
WH40K fans love to joke about them having sex with toasters.