One Piece episode 516, Jinbei went back to Fishman Island and ask Luffy to visit him after 2 years. Luffy left Boa Hancock  and decided to go with Rayleigh for his training to develop his skills. In a huge island of wilderness which inhabited by terrifying huge creatures, Luffy will train under Rayleigh for 2 years.

In this training, Rayleigh educated Luffy about the three powerful Haki (literal meaning: Ambition) and explained to him how each Haki works.

“Haki is a power that lies dormant in all the world’s creatures… “presence”, “Fighting Spirit” and Intimidation”… It is not different from the things that humans can naturally sense such as these… ‘The act of not doubting’. That is strength!

Luffy left his Straw Hat in the safest spot of the island and promised his friend that he will meet them on the promised place after 2 years.

High School of the Dead (H.O.T.D.) was introduced to me by a friend just this June. I only streamed the 12 episodes online but I haven’t watch the OVA yet. I also remember the series Walking Dead when I was watching H.O.T.D.  because it doesn’t show how did the outbreak happen in the first season.

High school of the Dead is set in the present day beginning as the world is stuck by a deadly pandemic that turns humans into zombies, euphemistically referred to by the main characteres as “Them”. The story follows a group of high school students, the high school’s nurse, and a young girl as they fight their way to safety through the deadly streets of Japan during a worldwide catastrophic event known as the “Outbreak”. As the cast tries to survive the zombie apocalypse, they must also face the additional threats of societal collapse, in the form of dangerous fellow survivors, and the possible decay of their own moral.