Assassin Signals are the Brotherhood currency used to call recruited assassins into combat in Assassin's Creed Brotherhood.
Ezio can recruit civilians in Rome and train them as members of his restored Assassin Brotherhood. Once available, Assassin Signals summon these allies to attack targets, create diversions or perform ranged assassinations during missions.
The interface displays a limited number of signal segments, which refill over time and can be expanded by advancing recruits. Signals are separate from money, experience and the guild’s economic income. Players therefore manage both the timing of summons and the long-term training of recruits.
The system is one of Brotherhood’s defining additions, alongside full control of Rome and the ability to send recruits on missions across Europe. Later games change or remove this exact signal mechanic, so it is not a universal Assassin’s Creed term.