* His anger at his father: Luke is angry and resentful towards his father, Poseidon, for abandoning him and never being present in his life. He feels betrayed and unwanted. This bitterness fuels his desire to seek revenge, even if it means aligning himself with the forces of darkness.
* His resentment towards the gods: Luke generalizes his anger towards Poseidon to all the gods, viewing them as careless and uncaring towards the needs of mortals. This resentment further motivates his quest for power and his desire to punish the gods for their perceived failings.
* His frustration with his own life: Luke feels trapped and powerless in his life. He feels misunderstood and unappreciated, both by his father and by other demigods. This frustration adds to his bitterness and makes him more susceptible to Kronos's influence.
* Kronos's influence: Kronos, the Titan Lord who is seeking to overthrow the gods, uses Luke's bitterness and resentment to his advantage. Kronos manipulates Luke's emotions and promises him power and revenge, giving him a sense of purpose and making him a willing participant in his plans.
In essence, Luke's bitterness stems from a deep-seated sense of abandonment, frustration, and resentment towards his father, the gods, and his own life. Kronos exploits these feelings to turn Luke against the Olympian gods and make him a powerful agent in his rebellion.