In which episode does Luffy activate Second, Third, and Fourth gear? Luffy activated Gear Second for the first time during the fight against Blueno of CP9, at the end of Episode 272–273. Luffy activated Gear Third for the first time during the fight against Rob Lucci of CP9, at the end of Episode 304.

Where did Luffy get the idea for gear second?

After watching the Soru ability, one of the Rokushiki powers, just once, Luffy figured out how the technique works. Using the power of his Devil Fruit, the Gomu Gomu no Mi, Luffy essentially created a similar power in Gear Second, but better.

Does 2nd gear shorten Luffy's life?

So to finally answer your question, the second gear still negatively affects luffy and chips away at his lifespan, but when compared to the time he first developed the technique, the effects are not that great.