Vampires are a staple subgenre of BL in any medium, and visual novels are no exception. From the earliest days of VNs, boys love and vampires have combined to make sizzling games that are worth playing. 

Anima Mundi - Dark Alchemist was a 2004 Karin Entertainment game localized to English by Hirameki International. The English release of this gothic horror visual novel was criticized by boys love fans for censoring or removing BL CGs from the game. The English version of the game has become all but lost media, as it is no longer available to purchase except through the occasional second-hand listing. 

Messiah was a 2006 game from CORE, from parent publisher Orbit. As the company is no longer active, Messiah is quite difficult to find, as you have to hunt it down second hand. It has also never been localized into English, making things more difficult. Despite these obstacles, the game has a cult status among BL visual novel fans as an early example of the vampire motif.

2016's Omega Vampire, from Karin Entertainment sub-company Karin Chatnoir Ω, has not been translated into English at this point in time. This title combines the vampire genre with the popular omegaverse trope, which originated in Western slash fandom and has now become a popular mainstay of boys love in many cultures. The protagonist of the game is voiced by Sawa Manaka, whom BL fans will recognize from games such as DRAMAtical Murder and Sorcerer's Choice. 

Red Embrace is a relatively short 2018 Argent Games release, the first in what would become a series of more ambitious Red Embrace games. It's a boys love / yaoi visual novel with four possible love interests and a variety of endings, as the main character is drawn into the complex, dark world of the city's vampires. 

Also from 2018, the far more expansive Red Embrace: Hollywood, from Argent Games, allows the player the option of making the game BL, as all three of the love interests are male and the player can customize the gender and appearance of the main character. The game is highly interactive and features explicit sex scenes, but be warned that things can turn very dark - don't look to this vampire drama for happy endings. 

While there aren't technically any vampires in Nitro+Chiral's 2021 Slow Damage, one of the supporting characters has an affliction where he desperately desires blood, and the resulting scene is sure to be of interest to vampire fans.

These are just a handful of the vampire boys love visual novels out there – make sure to check some of them out and sink your teeth into the world of bloodsucking BL!