Part of the game UI is to communicate to the user that their health deteriorates when in a dark area. We broke the death into 4 stages. 25 / 50 / 75 and 100%. This sprite is the 25% stage where neon blue (the enemy forests signature colour) is taking over the character = journey towards death.
50% will be blue up to the waist area, 75 will be the shoulder and 100 = totally blue and so death.