Percy Jackson and the Last Olympian

Violence (0–5): 3 — The most battle-heavy book in the series. Large-scale warfare, monster combat, and character deaths are central to the plot. Violence remains in the fantasy/mythological tradition — swords, magic, creatures — but it is sustained and intense. Several named characters die, including ones readers will care deeply about.
Drugs / Alcohol (0–5): 0 — Not present in any meaningful way. (Ambrosia and nectar, the food of the gods, appear as in previous books but purely in a mythological context.)
Sex (0–5): 1 — Romantic feelings and a significant kiss between Percy and Annabeth. Age-appropriate and sweet; nothing more.
Language (0–5): 0 — No profanity; clean throughout.
Themes (0–5): 3 — Death, sacrifice, loss, and grief feature prominently. Several beloved supporting characters die in the final battle. The emotional weight is considerably heavier than earlier books in the series, and some children may find the deaths of familiar characters genuinely upsetting. Also explores themes of loyalty, destiny, free will, and what it means to be a hero.