Does Hidden Blade allow you to choose a target when it resolves (like the asker thought Void Seeker worked)?

Ruling: No. Hidden Blade requires you to choose a target when it finalizes, not when it resolves. Both Hidden Blade and Void Seeker follow the standard targeting rules.

Nuances:

• Cards like Falling Star work differently because they use Reflexive Triggers (indicated by "Do This:"), which create separate chain items that handle targeting differently
• Generally, if a spell or ability will act on a unit that can't be automatically determined and is chosen by you alone, it targets on finalize
• Bullet Time is a separate ruling case and doesn't follow the same pattern