|Manga||Chapter 00: Black Lagoon|
|Anime||Episode 01: The Black Lagoon|
|Japanese Anime Voice||Taiten Kusunoki|
|English Anime Voice||Mark Acheson|
Boris (ボリス, Borisu) was Balalaika's second-in-command.
He could be easily identified by the large scar running from the right side of his forehead to his left cheek.
Like Balalaika, he had served in the former Soviet army in the Afghan Civil War. She still referred to him as "Sergeant" rather than by his name, suggesting that he was her former platoon sergeant. He was very loyal and protective of Balalaika and often worried for her safety when she decided to fight in the field.
He was a calm, broad-built man with a deep Russian accent.
- In Omake 6, he appeared as a 'weak girl-ish boy' who later joined the army to man-up. This caused a great amount of distress amongst Rock, Revy and Balalaika due to how handsome or beautiful he looked. They then told him to stay like that.
- Boris has a strong resemblance to Bayman from the Dead or alive series.
- In the First Popularity Poll, Boris ranked 18th place.