When do Shield and Yi Legend abilities activate - before or after defend and attack triggers resolve?

Ruling: Shield and Yi Legend abilities activate when a unit gains the defender designation, which occurs before attack/defend triggers resolve.

Sequence:

• Unit gains defender designation
• Shield and Yi Legend abilities activate (Yi only if defending alone)
• Attack/defend triggers resolve

Nuances:

• Yi Legend ability requires the unit to be defending alone, while Shield does not have this restriction