Since the anime only covers about a third of the source material, fans looking for the complete experience should turn to the manga.
You can find the complete series through Kodansha , which provides the full context of the graduation and wedding arcs. Ending tonari no Kaibutsu-kun
Give you a of the final volume. Compare the manga ending vs. the OVA . Since the anime only covers about a third
The "monster" family isn't left behind. Natsume and Sasayan’s relationship remains beautifully ambiguous but hopeful, while Yamaken finds his own path, moving past his unrequited feelings for Shizuku with grace. Why the Ending Resonates while Yamaken finds his own path