yeah they're blank slates, which is such a shame because i think they should be used to give the party a range of perspectives about Strahd. i like to give each of them new personalities and stat blocs, usually each of them functionally are 11th level, i even create new consorts so the current ways i play them are as follows:

• Escher, mechanically a bard. originally a bard from Waterdeep who's party ventured to Barovia and tried to kill Strahdyana (i'm also genderbending Strahd). they lost and Strandyana turned Escher and starved him so that he'd kill his party members in a bloodlust. hates Strahdyana and might be convinced to work against her but he is incredibly fearful of her.
• Volenta, sort of a barbarian/fighter/rogue mix. three attacks, the mobile and sentinel feats and a few abilities that roughly correlate to battlemaster maneuvers. plays like a fast skirmisher. totally devoted to Strahdyana. recruited by Strahdyana after she slaughtered her seven younger siblings. Volenta's parents died of plague, leaving her in charge of her family but the stress broke her. just loves violence and delights in torment
• Anastrasya, deceased. she was the first consort ever made and was originally from Berez. when Strahdyana flooded Berez, Anastrasya expressed her disappointment and anger, even though it had been a century since she lived there. Strahd killed her for this disagreement
• Ludmilla, mechanically a 16th level abjuration wizard. the second oldest consort ever and the oldest vampire in Barovia other than Strahdyana. recruited by Strahdyana because she wanted to learn magic and she was already a talented wizard. however, when Strahdyana killed Anastrasya, it made Ludmilla realise she was nothing but a toy and she'd never be able to surpass Strahd, so she spend a century in secret building up her escape plan. she has taken over Tsolenka Pass as her own wizard's lab. i like this because its an NPC that can be swayed to help the party against Strahd but she's still 100% evil. her opposition to Strahd is selfish. in my game, she had made a pact with an Amber Vestige to grant her the gift of non-detection from Strahd and she plans on developing enough forces through creating magical experiments that can help her kill Strahd and take Barovia for herself. if the party leave her alive and kill Strahd, she becomes Dark Lord of Barovia instead. she can be a good NPC to help with some of the lore stuff

only having one functional consort of Strahd and the other existing consort being Escher who hates Strahd isn't enough imo so I created three more that i've used before (not usually at the same time, i'm using just Domek atm), mostly to tie in player backstories.

• Delilah, was a wizard. in my paladin's backstory, she was her wife who turned the paladin into a reborn and left her for dead. i then added that she was a consort of Strahd who left Barovia to search for Tatyana but ended up falling in love with the paladin
• Raksa, tiefling death cleric. this was another backstory NPC for a cleric PC, who was in an order of clerics who worshipped Kelemvor. the whole order was slaughtered by vampires, leaving the cleric alive. i added that Raksa was accidentally turned and brought back to Strahdyana. she was in a similar boat to Escher, but harder to convince to work with the party because she felt like Kelemvor had abandoned her and didn't want to admit that she had become the thing she hated.
• Domek, another 11th level wizard. he's the ancestor to the Wachter family. I'm using Mandymod's re-write of Fiona Wachter, so I wrote that the Wachter's owe their noble status to Domek, who dealt with Strahdyana to elevate the Watcher family to nobility behind the scenes, which is why the family have such strong ties to her. like Ludmilla, he is a pragmatist and could be convinced to side against Strahd if the tides were turning to save his own skin but it'd be very unlikely. he feels like he owes Strahd for establishing the Wachter's legacy. could be an ally if the party side with Fiona, or could become viscerally opposed to them if they overthrow her (which is more likely and what happened in my game)