If Sett is on the battlefield with an allied unit that has a buff counter, and an opponent's Yasuo kills that buffed unit during a showdown, does Sett lose his +1 might during that showdown?

Ruling: Yes, Sett loses the +1 might as soon as the buffed unit dies during cleanup of that showdown.

Sequence:

• Yasuo kills the buffed allied unit during the showdown
• Cleanup occurs
• The buffed unit is removed, causing Sett's might to decrease
• Sett's might is reduced during the same showdown

Nuances:

• Cleanup and Layers are different mechanics - the cleanup happens but layers determine when stat changes apply
• If multiple cleanups are needed, they happen consecutively (one after another)
• The timing is within a single cleanup phase, not multiple separate cleanups