I understand it.
I mean, when we take Triple Strike, Firebrand’s mana cost increases.
While for Pyre, mana is removed separately, 10 for hitting and 3 for the cost of Puré itself.And the cost of the firebrand itself remains 0.
I suggest that when taking a Pyre node, Firebrand’s cost becomes 10 mana. And 3 mana for Pyre himself.