When activating a rune ability (with [Add]) that triggers Sivir's legend ability, does priority immediately pass to put the trigger on the chain, or does the trigger stay pending until priority is passed?

Ruling: When you activate a rune ability with [Add] that triggers Sivir, the trigger goes pending on the chain and is finalized during cleanup without passing priority. You maintain priority throughout.

Sequence:

• You have priority and activate the rune ability (maintain priority)
• The Sivir trigger goes pending on the chain
• During cleanup following the rune ability, the Sivir trigger is finalized (priority does not pass when finalizing items)
• You still have priority

Nuances:

• If you activate the rune ability while paying a cost during resolution of another spell or ability (e.g., Flame Chompers), the pending Sivir trigger will be finalized in the cleanup that follows that spell/ability resolving, and then whoever controls the most recent item on the chain gets priority
• All [Add] abilities use the chain - they finalize and resolve immediately without passing focus or priority, but they still go through cleanup