Ballista Ballista , plural ballistae , are weapons used primarily by elves , but may be designed with dwarven and even human engineering . Based on the same mechanical principles as the crossbow but on a larger scale , ballistae are the siege weapons that hurl stones or metal projectiles toward their targets . They were first built by the night elves , but the forces of both Alliance and the Horde have developed ballistae of their own design . After cranking back lever arms held tight in skeins of leather or sinew , the crew loads a projectile into the ballista ' s central track . When the trigger is released , the stored tension in the skeins of the ballista propels the projectile downrange at incredible speed . Alliance ballistae . Ballistae were used during the second war . Ballista launch steel - tipped bolts to impale all in their path . As they require an awesome amount of force to be placed upon their tremendous bowstrings , these machines of war are reinforced with lumber from the precious ironwood trees . The ballista , a product of human design and elven craftsmanship , is a symbol of the unity between all those who have allied themselves against the Horde . The dwarves prove to be another valuable ally , in that they may be employed to design improved missiles which make the ballista the most devastating weapon of the Alliance . The technology was adapted into the field , crew , siege versions seen after the Second War . Field ballistae . A ballista type used by forces after the third war . A field ballista can be used by small , two - man crew and is usually directed toward less - fortified secondary targets such as mid - field entrenchments . Typically , a field ballista crew travels on two mounts , one pulling the collapsed field ballista like a travois while the other carries a supply of projectiles . Crew ballistae . A ballista type used by forces after the third war . Crew ballistae are larger , steel - framed versions of the field ballista . The steel frame is sturdier than wood , and metal housings surrounding the skeins protect them from being damaged by the environment or enemy fire . The four men who wield a crew ballista are divided into two " brutes " who crank the lever arms , the " slot " who loads the bolts into the track , and the " sharp " who aims and triggers the weapon . Siege ballistae . A ballista type used by forces after the third war . A terror of the battlefield , the siege ballista can hurl enormous bolts over tremendous distances to penetrate all but the thickest armor . Each arm of a siege ballista is eight feet in length , and the entire weapon must be mounted on a wheeled cart to be portable - and then anchored into place on the battlefield so that it isn ' t thrown forward when it is fired . Ballistae ( High elven ) . The high elf Ballista helped the high elves fend off Arthas as he tried to attack their capital of Silvermoon in Warcraft III . It is a siege unit that has a long range , built in the high elven barracks . The blood elves did not have ballistae in their Frozen Throne campaign in Warcraft III , although they strangely did have glaive throwers in the undead campaign . Ballistae ( night elven ) . Crafted from the sturdy ashenwood trees , the night elves ' ballistae are deadly siege machines built to fling heavy bolts of ironwood at both enemy forces and structures . Ballistae are considered an invaluable asset to the night elf Sentinels due to their mobility and accuracy in tense combat situations . Night elves largely replaced the weapons with glaive thrower s after the Third War . Ballistae in World of Warcraft . Ballistae can be found in various places in the World of Warcraft , sometimes broken . Some are mobs , such as the Scarlet Ballista .