For Tryndamere's excess damage ability, if the battlefield has 2 units with 3 Might each, does excess damage count after killing one unit (since 5 damage remains), or must there be 5 excess damage after ALL units are killed?

Ruling: Excess damage only counts after ALL defending units are killed. You must assign lethal damage to all units before any damage can be considered "excess."

Sequence:

• Assign damage to first defending unit until lethal (3 damage)
• Assign remaining damage to second defending unit until lethal (3 more damage)
• Only after both units have lethal damage assigned can the remaining damage (2 in this case) be considered excess
• If Tryndamere attacks with an ally who can kill one unit, then Tryndamere's 8 damage against the remaining 3 Might unit would result in 5 excess damage

Nuances:

• Units cannot have more damage assigned than minimum lethal unless no further units remain to have damage assigned
• Units that cannot be dealt damage (like immune Kayn) are exempt from mandatory damage assignment rules, meaning you can choose whether to assign damage to them or not, but they don't block excess damage calculation if you choose not to assign to them