Buki'vak

Buki'vak was a sea-dwelling demon in the lore of Dota 2.

Lion versus Buki'vak
Some time after Lion got his revenge on the treacherous demon and took its hand for his own, he heard of the power of another demon named Buki'vak and went to his abode through the Infernal Hollow found far away beneath the Sunken Cities, seeking more fresh parts to harvest for another demonoplasty. Lion fought tooth and nail with Buki'vak and successfully defeated him in battle, allowing him to claim his hand. Grafting the demon's hand into his own, Lion was afflicted with the Malignant Corruption, causing unseemly shards of Obsidian to proliferate on his body, twisting his already unrecognizable form into something far worse.

Heroes
Ever hungry for demonic power, thought that Buki'vak and his power was nothing more than a means to his twisted ends, harvesting the demon for raw parts of power.

Abode
The hellish abode of Buki'vak lies beyond the Infernal Hollow that's situated deep within the Sunken Cities. From there, he forever spreads his corruption throughout the sea.

Appearance
Based on the corruption that Buki'vak's hand afflicted on Lion's body, the demon had shards of Obsidian protruding throughout his carapace, including a pair of horns with the tips of his horns being red. His left hand had three fingers that were red and edgy, while the rest of his hand was purple. There are spikes all over his forearm as well as his knuckles.

Powers
Like most demons, Buki'vak had this ability to spread corruption, which he does to the sea around his hollow. His severed hand, once it was grafted into Lion's arm, inflicted a so-called “Malignant Corruption” upon the mage's form, growing Obsidian shards on his body. It being malignant implies that it's deadly, but Lion is fine so far.