
Oyaga Saikon. Koibito ga ore wo "Onii-chan" to Yobu yo ni Natta is a Japanese novel of 99,574 characters, with 4,796 unique words and 1,327 different kanji. Its difficulty rating on Jiten is average, 2.2 out of 5. The full vocabulary list ranks all 4,796 words by how often they appear, and you can study them on Jiten or download them as an Anki deck.
Here are some of the words that appear most often in this media, as well as a sample of its rarer vocabulary.