If an opponent casts Falling Star to deal 3 damage to two 4-might Noxian Hopefuls, then plays Thousand-Tailed Watcher (which reduces might), do both Hopefuls die?

Ruling: Yes, both Hopefuls die. When Watcher resolves and reduces their might to 1, lethal damage is checked during cleanup after the effect, and the Hopefuls have 3 damage marked with only 1 might, so they are killed.

Sequence:

• Falling Star deals 3 damage to both 4-might Hopefuls (they survive with 3 damage marked)
• Thousand-Tailed Watcher is played and resolves, reducing their might to 1
• During cleanup after the Watcher effect, lethal damage is checked
• Hopefuls now have 1 might with 3 damage marked, so they die

Nuances:

• This same interaction applies to other damage-then-might-reduction combos (e.g., Hextech Ray followed by Stupify on a Hopeful also kills it)
• The order of playing cards matters for preventing opponents from making incorrect decisions about unit survival