16 Apr 2021
If a spell has additional costs, apply those increases before applying cost reductions.
16 Apr 2021
Killian, Ink Duelist can't reduce the colored mana requirement of a spell's mana cost.
16 Apr 2021
Killian can reduce alternative costs. For example, if you choose to pay the {1}{B} alternative cost for Baleful Mastery while targeting a creature, that cost would be reduced to {B}.