Dawnstrike Vanguard

• WOTC Official Reminder Textofficial rules
  Lifelink — Damage dealt by this creature also causes you to gain that much life.

• WWizards of the Coast2025-07-25
  Official Ruling
  Dawnstrike Vanguard’s last ability will check as your end step starts to see if you control two or more tapped creatures. If you don’t, the ability won’t trigger at all. You won’t be able to tap anything during your end step in time to have the ability trigger. If you don’t control two or more tapped creatures when the ability resolves, the ability won’t do anything.

Rulings via Scryfall