“role / duty” in Japanese is 役, read yaku, eki (やく, えき). It is a Grade 3 Kyōiku kanji, taught in year 3 of Japanese elementary school, and appears in words such as 役所 (government office).
What does 役 mean?
げきで王様の役をする。
Same sound, different character — the classic trap. Compare them side by side: