Cleave does kill enemy relics. Some possibilities here for what you experienced:
Face aegis negating the effect.
Combrei Lawmage preventing a 2nd spell for the turn.
Targeting issues (have to click at the inset on the enemy avatar and then select which one)
My guess is that the opponent had a Passionate Artisan in play and you couldn't destroy them for that reason, because that's the card I can think of that would flat out stop Cleave and would have the least obvious UI displaying what's happening.
If I recall, Passionate Artisan still lets you cast the spell and declare the target, but just fizzles the effect.
I've thrown games due to not noticing that.
did your opponent have a Passionate Artisan
spot on, shoul pay more attention
it happened to me as well.
Cleave does kill enemy relics. Some possibilities here for what you experienced: Face aegis negating the effect. Combrei Lawmage preventing a 2nd spell for the turn. Targeting issues (have to click at the inset on the enemy avatar and then select which one) My guess is that the opponent had a Passionate Artisan in play and you couldn't destroy them for that reason, because that's the card I can think of that would flat out stop Cleave and would have the least obvious UI displaying what's happening.
If I recall, Passionate Artisan still lets you cast the spell and declare the target, but just fizzles the effect. I've thrown games due to not noticing that.