@Kalamel
Yes you are right about Tristan's studying. I just thought what I saw in chapters and not more. But we didn't see the things enough about his summoning. Maybe he studied so hard but failed (compared to Ivona).
However just as you said, he built his personality with being superior than Ivona. And he is nothing without her being under his feet.
That just shows him being such a useless person. He should have tried to surpass himself not any other person. And he feels pleasure when Ivona being humiliated (again, compared to himself).
(I don't know why I wrote that much, sorry if I offended/bothered you.)
And about 'Gaspal' you are definitely right, I have no answer to that