Assassin (アサシン), Silent Killer and Heroic Spirit of Assassinations, is one of the Four Cavalry classes among the seven standard Servant classes summoned for the Holy Grail War. Servants of this class are skilled at operating covertly, stealthy, and silently. This class is one of the weaker classes at fighting; as its members possess low attributes due to not having glorious legends as heroes; so it instead specializes in killing Masters rather than Servants. It is an oddity compared to the more formal knight classes who believe in fair duels and chivalry in combat; they will attack using the most unfair and favorable conditions; and with these conditions, it is possible for an Assassin to match and defeat other Servants. The Assassins' special class ability is “Presence Concealment”, which allows them to remain undetected when spying or preparing to ambush their targets.