What is it ?

A mod adding a new mob to work alongside the illagers, while adding various mobs and items related to him;

What does it offer ?

A raider vampire hostile mob which can be quite dangerous as just like zombies it won't just kill villagers but transform them, turning them into vampire villagers which might join the attack instead; not only that but this mod also features unique professions for these new vampire villagers such as the Alchemist (which can sell an immunity potion ; I find this villager too OP because it can also sell blaze powder which breaks the vanilla overworld-nether-end progression), the Slaughter (which I don't find that interesting since its too similar to a regular butcher villager), the Chronicler (which is some kind of historian , selling you a special card which grants you some vampiric abilities ) and the Bard (selling you a special lute and buying the discs you can find in game).

It also adds a new event called the Nightfall plague , which makes the fog foggier and vampires stronger, among other little fun details.
I would like to suggest making/adding a custom ambient track to play during this event just like how some bloodmoon mods add their own eerie sound ambience during the event, but that won't impact my review overall.

(I did not notice any major performance issues)

In conclusion

This mod adds a new mob to join raids which has its place, is good-looking and perfectly fits the fantasy vibe of vanilla minecraft (even if in all honesty Mojang would deem vampires too close to zombies and probably never add them, but one can dream); not only that but it features extra unexpected content to go alongside its new main creature.
The mod's page is also very clear about what the mod adds, which is always a plus in my books.

That said there's some issues with the main progression of the game, notably the Alchemist selling you a nether-exclusive item from the base game, and there's probably some ways I have yet to figure out on how to make the Slaughter more unique.
The lack of a config file to allow making these changes myself/customizing the various trades I don't like makes me hesitant to use it in packs or more serious future projects, if the mod gets updated to add one among possible balance changes/if I'm a dummy and the 1.21 Neoforge version already fixes these issues I'm willing to tweak this review.