Heart Thunder! Final Smash (ハートサンダー！ファイナルスマッシュ Hāto sandā! Fainaru sumasshu) is the attack that Cure Thunder uses in episode 3. She needs of her GamePact and the Stick/Rod Card to perform this attack.
Ki put her Rod/Stick Card at her GamePact then her rod appears she press the button and light blue lights are lit going upward until reach the Heart. She says "Sound ! harmony within my heart" and a yellow light is start to shine in the arc and Ki start to blow, Ki closes his eyes and says "Pretty Cure..." she puts the string of the arc, open his eyes and say "Heart.....Thunder!!" and then purifying the Muchijutsu.
- キュアサンダー：プリキュア... "
- キュアサンダー：ハートサンダー ！！
- Kyuasandā:Hibiki watashi no kokoronouchi no chōwa!
- Kyuasandā:Hāto sandā! !
- Cure Thunder:Sound ! Harmony in my mind
- Cure Thunder: Pretty ... "
- Cure Thunder: Heart Thunder!!
- Ki are the only to not have a attack upgrade.
- Ki is the most powerful of the group.