This is the definition you will find on the boards, HOWEVER SEE BELOW IT.
Definition of Taunt:
Taunt (added)
Taunt is a character attribute printed on the card. Taunt is a battle challenge performed by an Evil Character. A taunt targets an opponent’s Hero. You can only taunt when your opponent has no lost souls to rescue. The taunt it is your only battle for the turn. The opponent can accept or decline the taunt. If the taunt is declined, the Hero loses the battle and gains the special ability specified with the taunt attribute (e.g., “place opponent’s Hero beneath deck”).
But here is what the actual definition should be:
Here's what the Disciples pack says:
Rule for the Taunt Identifier:
Taunt: If no opponent has a lost soul in his territory, you may make a "Taunt battle challenge" with an evil character that has a Taunt identifier. A Taunt battle challenge is begun by placing the evil character into battle and declaring an opponent. The opponent may accept the Taunt battle challenge by placing a Hero into battle to fight the evil character. If the evil character wins the Taunt battle challenge, activate the special ability in the parentheses after the Taunt identifier. (If you decline any kind of battle challenge, you lose the battle challenge).
I hope this answers your question, and preempts a potential problem with a discrepancy on the boards as opposed to the accepted/actual rule
