Etherium
Etherium is a highly advanced form of Aegis Armour built into the Synskin of Officio Assassinorum Culexus Assassins. This, combined with the Culexus's innate Pariah abilities, means that psychic attacks pass right through them as if they were invisible.[1]
Sources
- 1: Codex: Assassins (2nd Edition), pg. 22