mournwhelk wrote:If my opponent casts a spell like Mortal Contract that doesnt have a duration, like until your next hero phase, and I fail to unbind it is there any wat for me to remove it? Does it stay in effect until the end of the game.
From page 233 of the Warhammer Age of Sigmar Core Rule Book (emphasis added):
If a spell is cast, the opposing player can choose one of their WIZARDS that is within 30" of the caster to attempt to unbind the spell before its effects are applied. To unbind a spell, roll 2D6. If the roll beats the roll used to cast the spell, then the spell is not successfully cast. Only one attempt can be made to unbind a spell.
You're only given one attempt to unbind a spell and you're only permitted to make that attempt before its effects are applied.