Sometimes noted to be more akin to "a heap of raw iron" than a sword, the Dragonslayer is a massive weapon that is tall enough to rival Guts' height and is wide enough to be used as a shield against projectiles.
Owing to the sheer size of the blade, the Dragonslayer has no crossguard; the blade itself, being both wider and thicker than the grip, functions as an improvised one instead.
A single bolt holds the blade and hilt together, and at the end of the bolt is a single chain link, which functions as the sword's sheath: by slinging a hook over his shoulder, Guts can simply loop the hook into the chain to allow the sword to hang off his back.
While of no use to anyone who does not possess the strength to wield it, the Dragonslayer is an extremely effective weapon to those who do. In combining the wielder's strength and the sword's heavy weight, it can damage enemies who shrug off attacks from more conventional weapons, most notably Apostles.
Due to being constantly used against Apostles and evil spirits, the Dragonslayer exists simultaneously in the Astral and physical realms and can thus damage beings that reside purely in the Astral layer.
In his youth, the blacksmith Godo lived in a castle town far from the hut he would one day call home. The castle town's sovereign, a king, sent out of proclamation to all of his vassals to forge a sword that would be capable of killing a dragon, and Godo's liege lord entrusted him with the task of doing so. Tired of crafting ornate weapons for nobles who sought elegance in their armaments, Godo took to the task seriously, creating the huge, but unusable, Dragonslayer. Offended at how crude and impractical the Dragonslayer was, Godo's liege lord threatened the blacksmith's life, forcing Godo to flee the castle town and settle down at his mine.
The Dragonslayer was kept in storage for years until it was discovered by Guts during a fight against an Apostle, whereupon the Black Swordsman wielded it with ease that shocked Godo, who thought the sword's weight made it unusable as a weapon. Since then, Guts has made effective use of the Dragonslayer against spirits, monsters and Apostles.
- It is assumed that Guts can wield the bulky Dragonslayer since he was shown using a regular sword as early as 6 years old (he refused to use a short sword) during his training with Gambino, a bastard sword at the age of 9 during his first castle siege accompanied by his mercenary group, in later years, a long sword when he killed a general just to give his prize money to Gambino, possibly a great sword followed by a two-hander until he was 15 where he used an over-sized two-hander to kill Bazuso. Ever since that, Guts has been using a sword bigger than his previous one. He has fought, carried, and practiced with oversized swords almost all his life, granting him a physique strong enough to wield it. Many have taken this as a symbolism of Guts' increasing burden of living.
- However, based on the laws of physics in our universe, it would be impossible, since the Dragonslayer has been speculated to weigh roughly 400 pounds.
- It is a common misconception that the Dragonslayer was once used to actually kill a dragon. This comes from online mistranslations.