War Turtles are units that carry your squads to enemy Outposts and territories, so you can raid them. They are invulnerable and can only attack at the start of a raid, where their fireball attacks instantly kill almost all enemy units. War Turtles only appear at the beach and only on the side of the attackers. Their purpose is to protect newly deployed friendly troops by killing enemy troops near or on the beach.
War Turtles have long enough range to target defending archers that are within range of newly deployed friendly squads. For this reason, it is unwise to position squads (archers or otherwise) within firing range of the beach, as they will be heavily depleted or even destroyed by the War Turtles.
Recent changes to War Turtles mean that to create a 'beach rush' (a defence plan where defending squads rush towards the beach quickly) that cannot be fired upon by War Turtles, movement delays must be set to 15 seconds, and squads must be placed initially out of range of the War Turtles. For this reason, 'beach rush' defence plans are quite rare and not advised.
War Turtles have two range zones: long range and short range. The long range zone covers the map far enough to target enemy archers that are within range of the beach, and the short range just covers the beach. The War Turtles can target enemies within the short range zone for 11.4 seconds after the raid begins, and after that they switch to the short range zone for a few more seconds, before retreating further out to sea (unable to attack). The War Turtles can each fire one fireball every 0.9 seconds.