View Solution

Play as the Barbarian. Set the second player("Local Player" so you control it) to a character that can attack with Psychic Combat, for example the Dark Cultist.

Have the Dark Cultist land on the space the Barbarian is standing on and Encounter the Character. Choose Psychic Combat, and win as the Dark Cultist. Choose to take a life from the Barbarian. The Barbarian then gets to roll a die, and on a 4-6 they'll defend themselves and not lose a life. The achievement then unlocks.

Reroll using a Fate point or exit and reenter the game before ending the turn(redoing the combat) if necessary.