Astray's Blade is the nineteenth episode of Gundam Build Fighters .
The next opponent for the Sei and Reiji team is Nils Nielsen, the young prodigy known as the Early Genius. His Sengoku Astray, which uses an arsenal of weapons and techniques based on Plavsky particles, is definitely a tough enemy. On the eve of the battle, Nils contacts Sei and Reiji and tells them he wants to ask them about something. If they tell him, he is willing to withdraw from the battle.
- Field 11: Castle makes its debut in this episode. The castle itself bears a strong resemblance to the Gundam Castle, the headquarters of the Musha Gundams in Mobile Suit SD Gundam Mk III.
- During the opening fight, the custom GN-005 Gundam Virtue is piloted by Georgios Laertius, whose character design is a nod to Tieria Erde's appearance in the Super Robot-esque in-story movie Celestial Being at the beginning of Mobile Suit Gundam 00 The Movie: -A wakening of the Trailblazer-.
- The Virtue itself is painted in the colors of the GN-005/PH Gundam Virtue Physical.
- During the restaurant scene with Fellini and Kirara, their fellow patrons resemble characters from Mobile Suit Gundam 00: Graham Aker, Daryl Dodge, and Howard Mason are seated at one table, while Kati Mannequin and a blonde Sumeragi Lee Noriega sit at the bar.
- This marks the first episode not to have a post credits scene.
- The next episode preview tagline ("Tell us it's a lie, Miss Aina!") is a reference to the Mobile Suit Gundam 0080: War in the Pocket episode ("Say it Ain't So, Bernie!").
- The Yajimon, Yajima Trade's mascot character resembles the Moomin only with the addition of Knight Gundam's helmet.
|Gundam Build Fighters Episodes|
Sei and Reiji | The Crimson Comet | Full Package | Gunpla Idol Kirara ☆ | The Strongest Builder | A Reason to Battle | World-level Ability | Encounters of Fighters | Wings of Imagination | The World Tournament Begins | Battle Royal | Discharge | Battle Weapon | Codename: C | Fighter's Radiance | Dad, We Meet Again? | Model of the Heart | Bloodhounds | Astray's Blade | Aila's Betrayal | Amid the Glittering Particles | Meijin vs. Meijin | Gunpla Eve | Dark Matter | Promise