Equip at Gear screen. Hold left on D-pad to switch to darts. Aim and press Heavy Attack to throw it.
Sleep darts are incredibly useful in battle, especially when facing multiple foes. Enemies or animals at your level or lower will fall asleep with a successful hit. Use it on a lone rival and sneak past while he snoozes or hit one or two targets so that you can concentrate on another. With the Animal Taming ability, you can use a sleep dart to get a companion. Put the animal to sleep and then hold the indicated button to make it your pet. Predators and defensive animals will fight by your side.
A meter counts down the time that the enemy or animal remains asleep. A slumbering foe will awaken with an arrow or melee attack, and you can assassinate them by pressing the Loot button. You can also apply Berserk to a sleeping enemy.
After killing an enemy or animal, click the left stick next to any corpse to apply the toxin.
When standing next to any corpse, click the left stick to apply the Flesh Decay ability. These poisoned corpses contaminate nearby NPCs, staggering anyone caught in the gaseous cloud. When a group of enemies are incoming, infect a body between them and you—giving yourself extra time to get away or go in for easy kills.
Approach an enemy undetected and click the left stick.
Approach an enemy undetected and click the left stick to turn him berserk instead of assassinating him. This causes the foe to attack his nearest target. Note that this cannot be applied to captains and commanders at enemy bases. Use this ability to cause chaos when infiltrating a stronghold. Note that you have a moment to apply berserk while being detected by a nearby guard. This is considered a hostile act, so if you use it on a soldier in an unrestricted area, they will come after you.
Equip at Gear. Hold left on D-pad to switch to darts. Aim and press Heavy Attack to throw it.
Hitting an enemy with a dart inflicts poison that periodically deals damage and contaminates nearby foes. This is a great way to begin a fight; hit a couple guards with the poison and let it spread to others. Bayek may not appreciate the smell, but the poison does not hurt him.