AI is key to HND. The NPCs of the world will be able to hear, see, track, and (in the case of animals) smell players. Along with the weather system of the game, there will be wind, and wind direction will always be shown on the player's HUD. Players can control whether or not they are downwind of animals, who will be able to smell them. NPC humans will use the most advanced tactics available to fight players. They will attack from range, “kite” players, attempt to find reinforcements, and use cover and dodging realistically. They will also attempt to sneak up on players, ambush them if they are making too much noise, and coordinate attacks between them. If a player brazenly walks up to a guard at the entrance to a cave, the guard might engage him on his own, but at the first sign of defeat or additional danger he would run inside, yelling for his reinforcements. NPCs will even try to “exploit” players by hiding in places that are difficult for the player to reach, such as on top of a cliff. They will then rain down projectiles on the player.
Overall, the goal of the AI in the game is to create realistic NPCs that can fight side by side with players. A last important feature to note is that NPCs will both recruit and be recruited by players to join battles. An army of NPCs might send a crier through the town to rally up reinforcements, announcing that a raid is about to happen on an enemy town. Similarly, players can talk to guards in a city and inform them of battles they will be marching to, and the NPCs may decide to join in.