Tripeace

Age Rating: 13+ or 16+

My Age Rating: 15+ (Be careful while reading it so you can skip immodesty which appears once or twice)

My Rating: 9/10

This is my absolute favorite manga ever! I've only read the eighteen chapters that are out but it's hilarious and awesome!! I definitely recommend it!

Objectionable Content:
A guy has to cross-dress frequently (Just so the enemy didn't recognize him and because a girl looked up to his female self and made her on her team.)
Immodesty is in like two pages
The heroes are against war (Wars that are started out of greed is what they are against)

Plot:

Nana, a young boy suffering from extreme amnesia, has forgotten his real name. After helplessly witnessing the unjust death of three children during one of his trips, he vows to eradicate all wars of the surface of the earth. He then joined Tripeace, a small group of activists whose members use all kinds of weapons and will stop at nothing, not even the violence, bring peace to the world. But soon, the new registration number 102,078 of Tripeace is faced with a dilemma: can we protect the peace at any price?