Lang (ラング, Rangu) is the old man that Jio and Ruby met in the Thorn Ruins. He lives there and has been researching the ruins for about twenty years when he first met them. He laughed about Jio's dream of world domination but later came to respect Jio. Jio changed him to believe in dreams once again.
Lang has a dream to learn more about the Thorn Ruins and to preserve them. He wants to gather all the information he can, but Sabaki is hindering him by destroying parts of the ruins because he wants the rumored A-rank O-parts that are supposed to be in the ruins. He begins to believe that dreams aren't meant to come true but Jio changes him into believing in dreams coming true. He then makes a bet to who will first make their dream come true with Jio.
Lang is first seen fighting with the Umbrella Brothers at the Thorn Ruins. He tried telling them there are not O-Parts in the ruins anymore, but they replied to blame Sabaki, since they are just doing their job. Moments before they finish him up, he was saved by Jio and Ruby.
Later at his house, he gave Jio and Ruby food and lodging. He also explained them who here were the Umbrella Brothers and Sabaki, and what was the Thorn Ruins. He explained them that he was researching those ruins for 20 years. After hearing Jio's dream, he bursted laughing and told Jio that dreams never come true.
Little bit later, he was seen laying on his bed and looking at a stone plate, then getting angry and throwing it out of the window. In the morning he came out looking for it and was caught by Ruby, who have found his plate and gave it to him, since she though it was something important to him. After that he took his equipment and went towards the ruins. Little after arriving at the ruins, Jio came, they again talked about dreams before they were interrupted by Jin. While Jin was went after Jio, who went inside of the ruins, he told Lang that he will kill him after he deals with Jio. Moments later Ruby arrived and Lang told her about Jio's fight.
Soon Sabaki arrived, surprised that Jin still haven't killed Lang, he took out his gun and shot him in the leg. After Sabaki and Jio came out of the burning thorns, he remembered what Jio have said and told to himself, that he won over him. But Sabaki again pointed his gun at him. Lang asked him to stop all of this, as his former research partner, but Sabaki replied that he won't stop as long as he have money and in that moment the master of the thorny vines came from the sky and grabbed him.
Three days later, when Jio and Ruby were about to leave for their journey, Lang wished good luck to Jio and his dream and also wanted to make a bet of who will make his dream come true first. While Jio and Ruby were leaving, he was thinking how strange Jio is and how hard it will be for Ruby with him. In that moment he realized that she was Ruby Crescent, daughter of a friend of him and that she was following his footsteps.