The Basilisk is a large monster in the Barren Region.
After the cataclysm, the Basilisk appeared to terrorize the Barren Region. Trade ground to a halt and nobody in the area possessed the skill to slay it as only a Champion stood a chance against the monster.
When Connor arrives in the Barren Region, the Weirdling Tradesman informs him of the Basilisk and the problem it poses. Connor offers to slay the monster and the tradesman agrees to craft a Black Diamond Pike for Connor if he can get a black diamond and a strong metal shaft for him. The tradesman explains that only a black diamond can pierce the Basilisk's hide but only in its one vulnerable spot. After Connor gathers the necessary materials, the tradesman crafts the black diamond pike in exchange for Connor's old weapon and ten gold coins and reveals to Connor that the Basilisk's only vulnerable spot is right behind its head.
After leaving the Weirdling Village, Connor quickly locates the Basilisk and sneaks around behind it to climb the cliff it is standing up against. Wielding his black diamond pike, Connor drops upon the Basilisk from above, causing it to roar in rage. Before it can dislodge or otherwise attack him, Connor rams his black diamond pike through the Basilisk's vulnerable spot, twisting it as the Basilisk falls. Connor's attack kills the Basilisk and he cuts off its tongue for later use in a spell. Connor calls the dead Basilisk "a foul beast" and abandons his black diamond pike where it is jammed beyond removal in the Basilisk's corpse.