He is the antagonist in Markus' second and third chapter.
Leo was born March 21, 2010, the result of a short but passionate affair between painter Carl Manfred and a fan. Leo was raised by his mother; Carl recognized paternity and paid a generous child support, but did not see Leo again until he was a teenager, aged 16.
Due to his father's wealth, he was always asking for money, partially to support his drug addiction. He had a hard time accepting Markus, feeling as if Carl treated him much better than his own son.
Leo arrives at the house and walks into the backyard. He is high on drugs. He looks at Markus rudely and asks his father to give him some money. His father recalls giving him money already. Leo has already wasted away the money on drugs and his father refuses to give him more. This makes Leo angry and he starts to complain about his father taking care of Markus rather than him. He pushes Markus before claiming that his father never loved anybody.
He later breaks into his father's house to steal some paintings, justifying it as advance inheritance money. His father will ask Markus to ask him to leave. Leo is angry believing that his father only cares about Markus and decides to beat up Markus. If Markus follows Carl's order to not defend himself, Leo's father will die of a heart attack and when the officers arrive he accuses Markus of killing his father, resulting in Markus being shot.
If Markus defends himself by pushing Leo, he will fall backward, hit his head, and will immediately be knocked unconscious. Carl will feel upset that his son was injured and driven by the fear of harm coming to Markus, he tells Markus to run away before the officers arrive, but will still lead to the officers shooting Markus.
Later on, it is revealed in a magazine that Leo regains consciousness and gives the statement that Markus attacked him.
Night of the SoulEdit
In "Night of the Soul" when Markus visits Carl's grave, he will encounter Leo as he leaves. Although they do not exchange words, it is likely that the two still hold resentment for each other.
If Carl is alive, Leo will leave a video voice mail at the house saying that he is sorry about what happened last time. He will tell his father that he is getting out of the hospital after being rehabilitated from his drug addiction. He asks his father if he can come over tomorrow and says he is proud that he is his son.