Can I move a ready unit into battle using normal movement, then use Yasuo's Legend ability to move an exhausted unit to the same battlefield so both participate in the same combat?

Ruling: No, this is not possible. If you move using default movement first, it will start a showdown immediately, and Yasuo's ability cannot be used during showdowns. If you use Yasuo's ability first to move the exhausted unit, that will start the showdown without time to move your ready unit.

Sequence:

• Moving a unit with default movement starts a showdown immediately
• Once a showdown starts, Yasuo's Legend ability cannot be used
• Using Yasuo's ability to move the exhausted unit also triggers the showdown, preventing the ready unit from moving afterward

Nuances:

• Yasuo's Legend ability is not an action/reaction, which affects when it can be used
• The order of movement doesn't matter - either sequence results in only one unit participating in combat