While not Sinhala, the Percy Jackson Graphic Novels have very few words. A Sinhala-speaking reader can follow the art and guess the plot. This is a legal, easy alternative.
Dedicated Sri Lankan fans (often university students or advanced English literature teachers) have taken it upon themselves to translate the books into colloquial Sinhala. These translations are typically: While not Sinhala, the Percy Jackson Graphic Novels
If you want to avoid the risks of the "free upd" search, here are legitimate ways to enjoy demigod adventures in a Sinhala-friendly way. Dedicated Sri Lankan fans (often university students or