From the Russian, ГРУ, meaning Гла́вное Разве́дывательное Управле́ние or 'Main Intelligence Directorate'.
The only elite Ruski force not to split into individual components. A bunch of hard-assed bastards who use 'intelligence' to kick people in the face. Common equipment includes the infamous AK74SU.
Creators of ingenious pub-brawl fighting system called SG (Spetsnaz GRU).
Not to be confused with Grue.