Tripeace manga

Tripeace summary:

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 102078 of Tripeace is faced with a dilemma: can we protect the peace at any price?