Astral combat

Without moving you can engage another opponent psychically without using strain. When one of you reduces the others HP to 0 or less that individualse HP drop to half their current total rounded down, whilst the Victor remains unharmed. Both combatants must be willing and the combat takes place in real time but once started they are locked in combat until there is a victor. Both opponents are motionless and take no action other than to dodge, deflect or make checks to resist outside attacks but are fully aware of their surroundings. If you choose to break the combat you automatically default the bout and lose half your HP.