The Viridian Balmung is one of three Balmung upgrades as reward for completing the miniquest, Koschei's Troubles. It is obtained by detecting curses on the jewel (requires 90 Prayer), turning it into a green jewel, and handing it to Kharshai to unlock a new memory. This jewel can be retrieved from Kharshai when the player wishes to recolour Balmung. However, without the jewel, the Viridian Balmung can be changed into the Achromatic Balmung by right clicking and selecting the "Toggle-colour" option.
In Norse mythology, Balmung (or Gram) was the magical sword of the hero Sigurd, or Siegfried as known in Germany.
Wallasalkis are affected by the Balmung effect as if they were Dagannoth.
Unlike most Average-speedtwo-handed swords (including its original counterpart), upgraded Balmung uses a damage multiplier of 22.85 instead of the standard 22.35. All versions of upgraded Balmung share this trait, effectively giving them an approximate 2.2% weapon damage (equating to 3.3% ability damage) bonus over other tier 70 weapons.