The character can strike and melt back into the shadows.
If the character makes a successful attack while Hidden, then they can attempt a Stealth test opposed by the Observe of any enemies who would reasonably be able to notice the attack. On success, or if they roll more degrees of success, they remain hidden from those enemies. If the attack is a melee attack, then the character must forgo the advantage gained from the Hidden condition to benefit from this talent.
If the current Turn ends and the character is in a spot where they could not reasonably remain hidden, the Hidden condition is lost.