Thewebtoon is a kid that receives a seal or letter from her mother. She goes to meet her dad who she think is just a rich guy and want money for her family. She find out her dad was a hero and is left in a shitty state. He dies but knowing that she was his real daughter because she held on to his magic sword without dying because apparently those with his blood could wield it and not die a horrible death like everyone else. Now she with her royal uncle bringing her family and she want to pass this talking sword that to her potential Step Brothers.

Heir to the Dragon Slayer Sword

Yup that the one, thank mate!