Quote from : The Last Olympian Book

As for my brothers," Zeus said, "we are thankful"-he cleared his throat like the words were hard to get out-"erm, thankful for the aid of Hades." The lord of the dead nodded. He had a smug look on his face, but I figure he'd earned the right. He patted his son Nico on the shoulders, and Nico looked happier than I'd ever seen him. "And, of course," Zeus continued, though he looked like his pants were smoldering, "we must...um...thank Poseidon." "I'm sorry, brother," Poseidon said. "What was that?" "We must thank Poseidon," Zeus growled. "Without whom . . . it would've been difficult-" "Difficult?" Poseidon asked innocently. "Impossible," Zeus said. "Impossible to defeat Typhon.