The song examines how anger toward another person can give rise to impulses to retaliate or cause harm to them. While such impulses typically dissipate over time, they can, in rare instances, intensify beyond our control and lead to irreversible acts of violence. “Dark Soul” is an abstract lyrically written song featuring a color-symbolism system to communicate emotion and action directly onto its lyrics. White signifies innocence; Blue denotes negativity and coldness; and Red represents anger and acts of hostility. 

Chorus - "What's forged in anger, often crumbles the same way."
This echos how our impulse to harm is forged by rage but often dissipate over time with our anger.

Bridge - "White moon high, gonna tear a hole through the sky. Blue heart in your cold hand, Gonna put you down in white sand."
Sets an atmosphere of a pure white moon illuminating the environment and marking the ground where an individual will be laid to rest for the interpretation of their cold actions and heart by another.

Bridge - "Red wave high, gonna grip you around your throat. Gonna turn you over, gonna turn you down."

Red wave represents the rising anger within and emphasized by the desire to kill by raw strangulation. To 'turn someone over' means to surrender them to authority, in this case, to a "higher authority," six feet down.
This is clarified in the following verse where the last lyric signifies the direct action and the following bridge emphasizes the result to be absolute: death.
Verse 1 - In the buildup, the flames hint to the anger and action of the individual's hands. Desert wind represents their isolation and that the individual is standing outside the victim's residence, under the white moon, where their consciousness crawls through dark holes to justify their upcoming action by mentally blaming the victim for dragging him toward this point with the lies and deceit of their cold heart and negativity.
Chorus - In the final chorus, the Chorus is cut short to end on "often crumbles...". This is an expression of how there are exceptions to the commonality and narratively communicates that the individual attempts the act.

The contextual basis of the scenario is left open to interpretation: perhaps it's an affair discovered, a rejection handled poorly, slander or libel, or even pure mental instability and hallucination against an innocent party.