Obtained by cutting off the tail of Black Dragon Kalameet.
When wielded with two-hands, the Obsidian Greatsword requires only 14 Strength. The two-handed strong attack unleashes an area-of-effect attack reminiscent of Kalameet's fire breath and causes high stamina drain for anyone who blocks the hit. This attack uses 50 durability.
While the Obsidian Greatsword has no scaling, it has great base damage and good weight for a greatsword. Its low requirements make it a good greatsword for players who do not want to invest in either strength nor Dexterity. In particular, the lack of scaling means that even one-handed, the Obsidian Greatsword packs a punch. The next strongest greatsword, the Man-serpent Greatsword, would require 23 strength to match the Obsidian Greatsword's damage output two-handed and 34 one-handed.
Unusual for a unique weapon, the Obsidian Greatsword can be augmented. The weapon's ability to be augmented coupled with its high damage and relatively low requirements means that it is a good choice for augmentation builds.
|Somewhat quick horizontal slash.|
|Somewhat slow overhead smash.|
|Somewhat quick overhead smash.|
|Users slams the greatsword into the ground and emits black and gold fire from the weapon.|
|Jump Attack||Forward jumping smash.|
|Running Attack||User turns weapon 360° horizontally around self.|
|Rolling Attack||Quick overhead smash.|
|Slow horizontal slash.|
|Variation||Attack Values||Parameter Bonus||Damage Reduction|
|Obsidian Greatsword +1 (Dragon Scale ×1)||352||–||–||–||–||–||–||–||60||10||40||40|
|Obsidian Greatsword +2 (Dragon Scale ×1)||384||–||–||–||–||–||–||–||60||10||40||40|
|Obsidian Greatsword +3 (Dragon Scale ×2)||416||–||–||–||–||–||–||–||60||10||40||40|
|Obsidian Greatsword +4 (Dragon Scale ×2)||448||–||–||–||–||–||–||–||60||10||40||40|
|Obsidian Greatsword +5 (Dragon Scale ×4)||480||–||–||–||–||–||–||–||60||10||40||40|
- The Obsidian Greatsword is labeled as a greataxe in its item description, compared to it being labeled as a greatsword in the weapon's stats menu. This is probably a translation error.
- The Obsidian Greatsword has a similar, if not the same, moveset as the Bastard Sword (excluding two-handed strong attack).
- In-game description refers to it as a greataxe, even if it is indeed a greatsword.
|Dragon Bone Fist • Dragon Greatsword • Dragon King Greataxe • Dragon Tooth • Drake Sword • Moonlight Greatsword • Obsidian Greatsword • Priscilla's Dagger|
|Dragon Greatsword • Dragon King Greataxe • Drake Sword • Guardian Tail • Gargoyle Tail Axe • Moonlight Greatsword • Obsidian Greatsword • Priscilla's Dagger|