Killian, Ink Duelist; Target "Creature"
Killian's ability only affects spells targeting creature permanents.
Rule 109.2 says

If a spell or ability uses a description of an object that includes a card type or subtype, but doesn’t include the word “card,” “spell,” “source,” or “scheme,” it means a permanent of that card type or subtype on the battlefield.

Killian's ability refers to &quot;creatures&quot;, which is a card type, without using any of the specified words, so it means creature permanents.