When Hidden Blade targets a unit protected by Sett's legend ability (which saves it from death), does Hidden Blade still draw 2 cards?

Ruling: Yes, Hidden Blade still draws 2 cards. The target is legal when Hidden Blade resolves and attempts to kill it, so despite being saved by Sett's legend ability, the unit's controller can still be identified and draws two cards.

Nuances:

• This is different from situations where the target becomes illegal (such as moving back to base before the kill effect resolves), because you cannot identify information about an illegal target and therefore cannot identify its controller in that situation.