This is even worse than people panicking about not being able to use it:
the Dark - Hex-Sealed Fusion works randomly for Dark Paladin. Why RANDOMLY?!
Sometimes, it works when I summon this first, and then Gaia Origin's effect. Or sometimes the other way.
Is there an unwritten rule that special summoning fusion monsters is once per turn? Because if I'm able to stave them off for another turn, the affect WORKS EVERYTIME?
What am I doing wrong?
(Please, I'm still new to this and a little frustrated I keep losing games recently 'cause the gamble is in the effect working.
If you think someone not understanding this game is beneath you and a disgrace, just carry on. No need to be a wise ass).
Not sure if I understood the situation: If you're using this card + Gaia The Fierce Knight Origin (or any other warrior type monster), you should be able to summon Dark Cavalry because you can substitute Dark Magician.
Did you use any other card effects or skills that prevented you from (special) summoning?
To have a 100% success at summoning Cavalry with this effect you must be using a prismatic copy that you obtained with money. Not one that you obtained with gems.