English (Source)
Unholy Power can only target traps and towers under the influence of a Pyre of Darkness, and increases their Unholy buff stack by <Highlight>1</> <i>(Up to a maximum of 4 stacks)</>. Energy cost depends on how many stacks the tower already has:
1 stack: <Highlight>1</> Energy.
2 stacks: <Highlight>2</> Energy.
3 stacks: <Highlight>3</> Energy.
Polish Translation
Unholy Power can only target traps and towers under the influence of a Pyre of Darkness, and increases their Unholy buff stack by <Highlight>1</> <i>(Up to a maximum of 4 stacks)</>. Energy cost depends on how many stacks the tower already has:
1 stack: <Highlight>1</> Energy.
2 stacks: <Highlight>2</> Energy.
3 stacks: <Highlight>3</> Energy.