Idolize it with copy . Skill the card up using the 3 rd copy . Use the seal to get the fourth slot . Plop a veil on it . Alternatively , if you have an SR that has 3 stickers thats stronger than maru , it may be better to idolize those . If you ' re new , this maru card will help you in the future since it ' ll be one of the only cards you can plop a Veil Aura on , and if you ' re not new , it ' s only worth doing if you don ' t have any extra 4 slot cards without veil veil aura on them . <| sep |> The Japanese Invasion of China during the 19301940 s . Tens of millions of people died , biological weapons were used and a massive portion of a nation of what is now a billion people was occupied by its coastal neighbor . I have only ever seen it as a footnote in any literature on the subject . You get chapters on the European war , the Atlantic front , North africa , the Pacific , and only passing mentions of the conflict in China .