Balmung is a two-handed weapon made of bane oretuned to dagannoths, obtained from Queen Sigrid during the quest Blood Runs Deep. Level 75 Attack is necessary to obtain the weapon as it is required to start the quest. Balmung is obtained relatively early in Blood Runs Deep and does not require any further completion of the quest to use it. Balmung is required to complete the elite Fremennik taskAxe'll Grease, chop down the blossoming tree during Koschei's Troubles, and cut the subsequent white jewel.
Balmung deals 25% extra damage against dagannoths and 15% against Dagannoth Supreme with auto-attacks, and 12.5% against dagannoths and 7.5% against Dagannoth Supreme with abilities[1]. It also has a 30% increase in hit chance against them[2]. Because of these buffs, it is considered a good choice when fighting Dagannoth Supreme.
If a player destroys Balmung after Blood Runs Deep, they can retrieve it from Queen Sigrid in the castle on Miscellania. During the quest, it can be retrieved from Brundt the Chieftain. They warn the player that next time Balmung is lost, it costs 300,000 coins to recover.