Thunder Blade

Lightning Sword or Keris Petir in Bahasa Malaysia is a type of Lightning that BoBoiBoy can project against his enemies like Adu Du and Probe. When he turns to BoBoiBoy Storm, it's longer and stronger.

Alternate Names
In the subtitles in Disney Channel Asia, the Lightning Sword is written in such names as :

Thunder Dagger

Lightning Kris

Portugese Version
Espada Raio 

Keris Petir