The scenes of Luke training Percy were so expertly written. He wasn’t just training Percy, he was actively recruiting Percy. He fuels Percy’s anger and mistrust of the gods. He didn’t even need to alter how Percy saw the gods because he could already see the resentment Percy had of his dad, mirroring his own. He was absolutely sure he had Percy on his side but he didn’t account for one thing, Percy’s fatal flaw. Percy’s loyalty to his family and friends supersedes all else. Luke can’t betray Annabeth, almost kill him, Grover and Annabeth, put his mother in a dangerous position, and then expect him to be on his side. That is where he fails.