On a successful melee attack on a humanoid you can cast this spell as a reaction. Your weapon slices across their body, a duplicate of the person you hit made of shadow and puss appears 5ft. away from the person you duplicated.
The duplicate has all the same stats, class and race features , AC, actions, attacks, weapons, and any non ritual/concentration spells avaible at the time of casting. The duplicate has a quarter of the persons hit points and half their walking speed. The Shadow duplicate is controlled by the person who cast it into existence. On each turn the person who cast them can use a bonus action to order the duplicate to take any avaible action.
If the person who cast Transpose Echo is hit by a non-magical attack, the duplicate and the caster are forced to swap places. The duplicate will take any damage dealt on that turn.
The caster can only have 1 shadow duplicate at a time, the shadow has to be killed or dismissed before another one can be summoned.
* - the spell can be cast as a bonus action to some one you hit, and deactivated as a reaction when some one make a successful hit on you. ** - (A bladed weapon of any kind and a victim)