1 ONE PIECE : WILL OF D IN THE MARINE

No one know that Gol D Roger had another child besides Portgas D Ace except Roger Pirates and Monkey D Garp. 
The child was the eldest son of Roger and 10 years older than Ace. The boy had sailed with his father to Raftel since he was 4 years old. Roger had asked Garp to take Ace as well as Jack and told him to take Jack as his apprentice. Unlike his father, Jack wanted to become a marine. He wanted to change the marine and uphold the true justice. 
Name : Gol D Jackson (later become Monkey D Jack)

Parent : Gol D Roger

Mother : Portgas D Rouge

Little brother : Portgas D Ace

Adopted grandfather : Monkey D Garp

Adopted brother : Monkey D Luffy

Allies : Monkey D Dragon, Shanks , Rayleigh

Age : 30 years old from the cannon start (different age with Ace is 10 years old)

Weapon : Sword (Ace) , inherited from Gol D Roger

Mastered all Techniques : Geppo, Tekkai, Rankyaku, Soru, Shigan, Kami-e, Rokuogan

Mastered all type of Haki : Haoshoku Haki, Kenbunshoku Haki, Busoshoku Haki

Power level : Kaido , Shanks & 3 admiral

Marine ranks : Vice Admiral 
Devil fruit : Heal-heal fruit , later the fruit awaken became Life Life fruit. The user not only can heal a person but can kill or give life to all things. So far, this fruit was the strongest. It can kill and revive with a single touch. This fruit had dissapeared for a 800 years. Roger found this fruit in Raftel and gave it to Jack.