Yashchur, do you need a battle map for the tournament?
Summons on his turn? If it's "removed from battle," does the effect stop working?
Yes.
I totally don't get what's meant here...
If he has only 5 AP total and has such a slave, then in fact he'll have 4 AP.
Is this like some kind of "hidden" skill? Can he use it? Or does he need to learn it somehow?
He can use it like a regular skill.
How many of them can you throw per battle? Is it considered a ranged weapon?
It doesn't require a skill and has no charges, but it doesn't activate active skills.
Who are "Albus's enemies"?
In the context of this drama — anyone with a different origin.