Invincible, Starting with One Piece

“I'm Luffy. I'm going to be a pirate.”

“No, Luffy. You're going to join the Marines.”

“I don't want to join the Marines. Pirates are free.”

“The Marines are free, too. You can go wherever you want, and nobody will stop you.”

“But I want to recruit underlings and find treasure.”

“Sure, no problem. The entire Marines will be your underlings, and if you want to find treasure, the Three Admirals will go with you. So, Luffy, join the Marines!”

Garp coaxed and tricked Luffy, determined to get him to join the Marines.

Because that brat had beaten him up when he was still a little kid.

I, Wang Lufei, was seven years old when I became the King of the Marines.

…

Basically, he got bound to two templates: one for One-Punch Man and one for a local native. With those, it's impossible not to be invincible.