Clearly, there’s tools for it now.
First, we need a curve or sorts. There’s one 1-drop that’s an easy choice: Bloodsoaked Champion. Others… not so much. Not that you need any. This format is slow, and you aren’t trying to kill fast, so its just a good, resilient threat, like many of the other cards in the deck.
Other creatures we might want? For 2-drops, the Despoiler of Souls is a good start, but I’d like to play some Pain Seers as well. Sure, this is going to hurt against burn and other fast decks, but we’ll have lifegain, so no problem there.
For 3-drops Liliana is nice, but we’ll need more. Probably Herald of Torment. I love that card. Its just pretty bad right now, at least in my home meta.
Then, of course, Gray Merchant of Asphodel.
Spells? Sign in Blood, of course. It’ll help us draw cards for the Titan and it will also play the part of Underworld Connections a little bit. Maybe one Read the Bones as well. Of course, some removal and maybe a Whip of Erebos or two.
For sideboard, maybe a few lands (so that you can take out the painful draw and not lose because you can’t draw lands. Probably a somewhat transformative approach couldn’t hurt either. We have plenty of lifegain already, so you don’t probably need any of that. Some discard for control decks would be nice too.