Am I allowed to discard cards at any time, even if I am not compelled to do so?
For example, if Varys is already played and I have him on hand, may I discard him before the strategycard "Heads on Spikes" is resolved? To prevent the opponent from getting 2 power...
And if so, to which point may I do it? Even after it being revealed? Or do I have to discard him before I know if the opponent played Heads on Spikes?
Also, may I discard characters, items or locations that are in game under my control?