Official Riftbound ruling

What happens during combat damage assignment if my 4 MightMight unit has both Ki Barrier and Lotus Trap played on it this turn and my opponent has a 4 MightMight defender?

You can order the replacement effects on your unit. If Ki Barrier is first, your unit will take no damage and you will have 3 damage prevention remaining on your unit. If Lotus Trap is first, your unit will take 1 damage and will have no damage prevention remaining on your unit.

With the Vendetta rules update, we’ve streamlined how replacement effects that apply to damage work in combat. Specifically, any replacement effect that would apply to combat damage being dealt will apply instead to combat damage assignment. This was already the case for prevention effects like Ki Barrier or Counterstrike, to prevent several strange edge cases. Now, damage increasing replacement effects will also apply during damage assignment.

Riot's question and answer, word for word, from theVendetta Rules FAQ and ClarificationsCore Rules 465.2.c.4.a, 465.2.c.5 (as numbered in August 2026)

The cards

  • Ki Barrier
    Ki Barrier

    Spell

    Reaction (Play any time, even before spells and abilities resolve.)

    Choose a unit. Prevent the next 7 damage that would be dealt to it this turn. (Opponents can assign it extra combat damage to kill it.)

  • Lotus Trap
    Lotus Trap

    Spell

    Hidden (Hide now for Any RuneAny Rune to react with later for 0 Energy0 Energy.)

    Reaction (Play any time, even before spells and abilities resolve.)

    Choose a unit. Double all damage that would be dealt to it this turn.