Balmung does not need to be equipped throughout the entire fight; to make progress towards the achievement, it only needs to be equipped when Dagannoth Supreme dies. It is possible to get this achievement when killing Dagannoth Rex or Dagannoth Prime by switching to Balmung while they are in the middle of their death animation.
The different colour variations consist of:
The different colour variations can be obtained by speaking to Kharshai after the miniquest Koschei's Troubles. Kharshai is located in Rellekka in the basement of Skulgrimen's Battle Gear, just north of the longhall.
- The name of the achievement comes from the colours of the Crimson and Viridian Balmungs, red and green, which are shared with two lights on traffic signals.