When Warwick and Anivia both have on attack abilities, can you order them so Anivia damages units first and then Warwick kills the damaged units, or does Warwick's ability not trigger if no units are damaged yet?

Ruling: You can choose the order that multiple on attack triggers go on the chain and resolve. Both abilities trigger and go on the chain regardless of whether their conditions are currently met, because they don't target and instead do "programmable choice based on characteristics" at resolution.

Sequence:

• Both on attack abilities trigger when you attack
• You choose the order to put them on the chain
• Place Warwick's ability on the chain first, then Anivia's on top
• Anivia's ability resolves first, damaging units
• Warwick's ability resolves second, killing the now-damaged units

Nuances:

• The abilities don't require their conditions to be met when they trigger, only when they resolve
• Neither ability targets, so they can be placed on the chain without preconditions being met