Tigui is a technology in Age of Empires II HD: The African Kingdoms that is unique to the Malians and can be researched at the Castle. Once researched, it enables Malian Town Centers to fire arrows at nearby enemy units without the need of garrisoned archers and/or Villagers, allowing it to participate in base defense when the player is raided by an opponent. It also increases the number of arrows fired from a Town Center by 5.
Tigui is very handy to have if the player is anticipating a late-game raid by the enemy and wants more defensive power to their base. Town Centers upgraded with Tigui can fire off arrows at nearby targets on their own without the need for garrisoned Villagers or the like, allowing for uninterrupted resource gathering, though purchasing it is largely unnecessary if the player already has a solid defense of towers and Castles at the ready.
In essence, a tigui was a master of a Malian house. In real life, they usually took charge of a house, making sure everything ran smoothly. This is represented in the game through the fact that the Town Centers now have a greater individual autonomy and defense, firing arrows without the player needing to garrison units or ring the Town Bell.