At the end, when the gods are called upon to fight the giants, Jason and Zeus fight Porphryion, King of the Giants, with Zeus shooting his Master Bolt to kill him. Jason manages to make a good impression on his father. Later, when Zeus says that Apollo must take the blame for what has happened, Jason risks his wrath by saying that appointing blame doesn't solve anything and calls Zeus's decision to punish Apollo for Gaea's waking unwise, but Artemis placates Zeus's anger and Jason notes that he might have pushed his father too far. In The House of Hades, Leo felt guilty about Percy and Annabeth and knew it was his fault, but knew that moping around wouldn't save him. However, after meeting Calypso, Leo felt a surge of anger towards Percy, and was mad at him for hurting Calypso. To make things worse, since Calypso clearly still had feelings for Percy, which made things ten times worse for Leo. Ultimately, however, Leo is the one to save Percy and Annabeth by flinging a screwdriver at the Doors of Death, managing to save them just in time. Leo was very happy when Percy survived Tartarus and whooped in happiness. Emmie shows Leo to Jo in The Dark Prophecy. Leo bonds with Josephine immediately for their shared love of mechanics and technology. Leo immediately goes to hang out with Jo. The two later help Calypso go to the infirmary. They later help rebuild Festus.

After that, Percy and Leo were friends with no problems and they defeated Nike with the help of Frank and Hazel. Leo became sarcastic and joking with Percy, calling him "Water Boy", which he told him not to call him, then calling him "Aquaman", which he hated more. Leo was also miffed and asked him why he had to destroy the plumbing when he did. Percy also joked that if a statue engulfed people in fire, he should send Leo, and Leo jokingly said he loved him too. Leo was also grateful when Percy got everyone in the crew, including him, gelato, and said that it made his whole day better. Leo also joked about how Percy's zodiac sign was Leo's name. However, Leo kept his suicidal plan to sacrifice himself from Percy. Percy was devastated when Leo died, and was initially angry at Hazel and Frank, but his anger subsided when they cried and agreed that it was a plan Leo would've done. Percy was hopeful that Leo was alive and said that if he lives, they can take turns strangling him.Leo was given fake Mist memories of Jason Grace being there for four months before he left, and Leo and Jason became best friends. They would joke about Piper, and Jason would be fine with Leo's annoying jokes. In the Mist memories, Piper and Jason had started dating a few weeks before the beginning of The Lost Hero. Even though Leo was happy for them, he felt like the third wheel and that they didn't need him anymore. Leo says it is his fault for Percy and Annabeth falling into Tartarus, but Nico tells them they are not dead. He still blames himself though and knows that the price for saving Hazel and Frank had been Percy and Annabeth. The six demigods decide to heed Percy's advice and Leo tells Festus to raise the sail so they can save Percy and Annabeth from the House of Hades. In The Mark of Athena, Leo was suspicious of Nico’s loyalties, due to knowing about both camps, and thought rescuing him was a trap. However, after Hazel fought with him and Jason, Leo decided to rescue him for Hazels sake and apologized to her, even though he thought he was suspicious for a good reason, and knew he had to travel fast to rescue him before it was too late. Leo even helped pinpoint Nico’s location with Hazel and Frank, and rescued him, Percy, Jason, and Piper On Nico's end, he was very grateful that Leo rescued him and thanked everyone, including Leo, for rescuing him. After Percy and Annabeth fell into Tartarus, Nico reassured him that they were alive and that if they were dead, he would feel it. However, Leo was still creeped out by Nico and did not like how he hesitated if Percy would survive.

Hammer - His primary weapon is his 3-pound club hammer, which he summons from his tool belt from time to time. Magical Toolbelt - He has a magical tool belt that he uses constantly. He can pull simple tools from the belt, as well as food, medical supplies, and breath mints. The belt is seemingly endless and he doesn't know where it all comes from. However, larger items, especially things that don't have to do with mechanics, require the belt to recharge or "cool down." It is also known that big items, such as chain-saws, or magic items, like Jason's sword, Ivlivs, cannot be pulled out of the belt. This is similar to Nico, as in The Tower of Nero, Will states that Nico slips into Italian when he's really upset. Jason has had daily audiences with Auster, the Roman god of the south wind, in connection with the Seven being able to proceed on their way to Epirus. Jason got very tan during his stint in Africa but very annoyed at Auster. After five days, Nico spoke to him and asked if there was any word from the king. Nico told Jason that they needed to leave soon and he sensed a bad feeling about the doors. He then said he had to convince Auster to help them, since he suffered too many humiliations. Jason then tried to discuss what happened in Croatia, saying he understood him and no one would judge him, but Nico grew angry, saying he doesn't belong anywhere and he would never understand since he was everyones golden boy, but no one ever accepted him except for Bianca, with no say in how he felt. Finally, Jason told Nico to take a chance and trust him, and that its better than hiding, and even called him out for always running away and hiding, but Nico snapped and said he would help him then leave forever. Jason began to think being friends with Nico was more trouble than its worth.Trilingual: Leo can speak Spanish, Greek, and English fluently, having learned both English and Spanish from his mother as a child, and knowing Greek naturally because of being a demigod. Enceladus | Porphyrion | Alcyoneus | Polybotes | Ephialtes | Otis | Damasen | Clytius | Mimas | Orion | Hippolytos | Thoon | Periboia Leo is the only person to physically appear in all 5 books of The Heroes of Olympus as he was in a video in The Son of Neptune. Jason has also seen in a dream that Reyna is on her way, and, assuming correctly that she will take advantage of being in the region by visiting Diocletian's tomb, leaves a note for her near the tomb directing her on where to go from there. As a child, Jason didn't remember much about his mother and Thalia, but he and Thalia were very close and would play hide and seek in his apartment. Beryl would try to tell Jason about his father, and showed him a storm at the beach, saying it was his father. When Jason was two, he tried to eat a stapler, in which he got his scar from. Jason was the only reason Thalia stayed home, because she thought he was cute and didn't trust Beryl to take care of him.