If Void Seeker targets a unit and the opponent plays Retreat in response (removing the target), does Void Seeker still draw 1 card even though there's no valid target for the 4 damage?

Ruling: Yes, you still draw 1 card. In Riftbound, spells never "fizzle" and you do as much as you can.

Nuances:

• The draw effect is not reliant on the unit in any way
• You draw no matter what happens to the targeted unit