If I play Stand United during a showdown with units that are already buffed (e.g., from Lee Sin's legend ability), do they get additional might from Stand United's effect?

Ruling: Stand United grants a buff to one friendly unit and creates a board-wide passive effect that makes all buffs (including existing ones) give +1 additional might this turn. A unit that already has a buff cannot receive a second buff, but it will benefit from the passive effect.

Sequence:

• Stand United targets one friendly unit and grants it a buff (+1 might)
• Stand United's second effect makes all buffs on the board give +1 additional might this turn
• Units that already have buffs from other sources (like Lee Sin) gain +1 might from the passive effect
• Example: A 1 might unit with Lee Sin's buff (now 2 might) becomes 3 might when Stand United is played

Nuances:

• You cannot place multiple buffs on the same unit
• The passive effect applies to all buffed units on the board, not just the one targeted by Stand United
• Lee Sin Ascetic is an exception that can receive multiple buffs