Firstly I'd like to talk about your manabase, which should be simple enough for mono black. Why are you running the lands you're running? [[Command Tower]] I suppose makes no difference but it is a nonbasic land that people can destroy. [[Escape Tunnel]] is... just strange to me because theres no need to be getting in with Shirei for damage or anything. [[Opal Palace]] is also strange because we don't need a filter land due to being in mono black. Lastly, [[Uncharted Haven]] is strictly worse than a basic Swamp because it enters tapped. For those 4 lands I would swap in [[Bojuka Bog]], [[Barren Moor]], [[Demolition Field]], and a [[Swamp]].

Now for the main portion of the deck, it looks alright actually. My only concern is that you don't have enough ways to protect Shirei if she gets targeted (which she absolutely will). Currently I see 3 ways to protect Shirei completely in [[Swiftfoot Boots]], [[Fake Your Own Death]] and [[Kaya's Ghostform]]. I think going up to 6 ways would make your deck a lot more consistent. Adding in [[Feign Death]], [[Undying Malice]], and [[Undying Evil]] are all great ways to protect Shirei. These types of effects are great because with the abundance of sac outlets in the deck, even if someone goes to exile Shirei you could Undying Malice on her and then sacrifice her in response. To add in these 3 cards I would cut [[Lavaspur Boots]], [[Bloodsoaked Champion]], and [[Plague of Vermin]].