Hrunting: Hound of the Red Plains ( 赤原猟犬フルンディング , ?) is the sword used by Beowulf to kill the mother of Grendel. Archer encountered it at some point in his lifetime, allowing him to add it to the database of Noble Phantasms stored within Unlimited Blade Works. He doesn't use it as a sword, but rather prefers to project and use it as a projectile Broken Phantasm from his bow. It is a pitch-black weapon, with a few small edges coiling around the thin core, spiraling around it and somewhat curving outward. He uses it from atop the Center Building in Fuyuki City during Fate/hollow ataraxia, and shoots it four kilometers towards Saber and Shirou on the broad bridge. Once fired, it turns into a magical bullet enveloped in a red light that reaches speeds of Mach 10 on the most direct path to its target, and it will continue to pursue the target, even if parried, repulsed, or avoided, as long as the shooter keeps aiming at them. While it is normally impossible to change targets after firing, he is able adjust for such possibilities and have a single path be capable of striking two enemies.
He can shoot it over five times in a row, and he adds more prana to charge the shot each time. The second shot has a charging interval of twenty seconds, and the time increases after he places more power into it, with twenty-five seconds for the third and thirty for the fourth. He can further adjust and charge the shot by taking five more seconds. These grace periods are the main weakness in the tactic, but the distance from the target requires either Saber destroying a number of buildings with Excalibur or the use of a Command Spell to increase her speed. It is fast enough to reach its target four kilometers away in less than a second, and it has enough force to stir the air and cause the bridge to rattle. It is strong enough to eventually overwhelm Saber on the fifth shot after deflecting the first four consecutive shots if she doesn't take action in order to protect Shirou, and the final shot is able pierce the four layered version of Rho Aias produced by Shirou while only being slightly averted from its target. The only reason Shirou is able to survive is that Archer is killed before the bullet can reverse itself to hit him.