When Harnessed Dragon is played and then killed by a reaction like Hidden Blade, does the dragon's kill effect still trigger?

Ruling: Yes, Harnessed Dragon's kill effect still triggers even if the dragon is killed in response to being played.

Nuances:

• This differs from Anivia, which requires being "here" (on the battlefield) for its effect to resolve
• If a unit is returned to hand (flashed back to base) in response to targeted damage effects like Comit or Void Seeker, that unit no longer takes damage