

Episode 10: “Crimson Killing Intent”
- 10 of 25
- September 8, 2012
- 23 min
- Aired
Contents
| Series | Sword Art Online |
|---|---|
| Episode | 10 of 25 |
| Japanese | 紅の殺意 |
| Original air date | September 8, 2012 |
| Episode length | 23 min |
| Studio | A-1 Pictures |
| Previous episode | Episode 9: “The Blue-Eyed Demon” |
| Next episode | Episode 11: “The Girl of Morning Dew” |
| Streaming | Crunchyroll, Netflix, Hulu |
“Crimson Killing Intent” is episode 10 of the anime Sword Art Online. It first aired on September 8, 2012.
Summary
The summary below describes what happens in this episode.
Kazuto Kirigaya duels Heathcliff before a large crowd. Heathcliff initially overwhelms him with the Divine Blade skill’s exceptional strength and defense, but Kazuto forces him onto the defensive before losing when Heathcliff evades his final attack. Kazuto subsequently joins the Knights of Blood, prompting Asuna Yuuki to ask why he previously avoided guilds.
Characters in this episode
Music in this episode
- OP 1“crossing field” — LiSAAnimeThemes
- ED 1“Yume Sekai” — Haruka TomatsuAnimeThemes
Where to watch
Streaming services that list Sword Art Online. What you can watch depends on your country. Acino does not host any video; each link leads to the service's own page.
Episode guide
All 25 episodes → · 22 of 25 episodes have a summary
About the series

This anime series is set in a virtual reality game where players are trapped and must survive. The story follows Kirito and his interactions with fellow players, including Asuna Yuuki, as they try to escape the game. What makes it distinctive is the high stakes, where death in the game means death in real life.
Read the article →References
- “Sword Art Online”. Kitsu. Retrieved October 22, 2026.
- “Sword Art Online”. MyAnimeList. Retrieved October 27, 2026.
- “Sword Art Online”. AnimeThemes. Retrieved October 23, 2026.
Episode titles and air dates come from Kitsu. The summary is written by Acino with AI assistance and checked so that it does not copy other sites.