2023-09-01 : Rowan's activated ability can't reduce the amount of colored mana you pay for a spell. It reduces only the generic mana component of that cost.

2023-09-01 : Rowan's activated ability counts the total amount of life you lost without taking into account any life you gained during that turn. For example, if you gained 3 life and lost 3 life earlier in the turn, the cost of black and/or red spells you cast this turn will be reduced by {3}.

2023-09-01 : Rowan's activated ability doesn't change the mana cost or mana value of any spell. It changes only the total cost you pay.

2023-09-01 : The value of X is determined only once, at the time Rowan, Scion of War's activated ability resolves.