Liesa, Shroud of Dusk
About the Deck
Liesa is a fairly resilient commander in that she avoids traditional commander tax, so once you have enough mana to play her you never have to worry about hoping you get land drops to replay her in the event of her likely death. However, her "life loss commander tax" can seriously add up, to the point that you may be unable to cast her if your life drops low enough. In my experience, Liesa will die a fair number of times throughout a game.
Due to the nature of Liesa's static ability and her life loss commander tax, you will likely lose a good amount of life to your own commander, but there are a number of life gain effects within the deck to hopefully offset this. The commander herself has built in lifegain and flying to make her harder to stop, which can go a long way towards helping you regain lost life. Various equipment pieces and auras can help work your way towards a commander damage kill while simultaneously increasing the life gain.
Vito, Thorn of the Dusk Rose and Sanguine Bond are all-stars in this deck. Besides enabling a few lethal combos, they can do a lot of work just chipping out significant chunks of people's life. One of those cards in combination with Children of Korlis in play is a massive deterrent for opponents who would want to hit you for a large non-lethal amount of life loss, as you can gain it right back and make them lose an equal amount of life. Cards like Gray Merchant of Asphodel, Exsanguinate, and Debt to the Deathless become a bit scarier since after you gain a significant amount of life, someone else is going to lose even more. Every time Liesa hits an opponent you are gaining 5 life and then you can hit another opponent for 5 more (I generally don't hit the same opponent she damaged to concentrate on the commander damage route on one player, but there are certainly instances where it is fine to double up).
Tainted Remedy incidentally hurts a number of people's decks randomly and helps with some combos in this deck. Swords to Plowshares and Solitude suddenly become far stronger when this enchantment is in play. I rarely regret having this in play, it generally does something every game.
Black/White decks don't tend to be the quickest to build up a board state, so I have found it important to run some amount of hatebears, effects that bring opposing pieces into play tapped, and spell-per-turn limiters. It may seem counter-intuitive to run something like Rule of Law when your commander hurts people for playing a ton of spells, but this is just one more barrier in the way of spell slinger decks and in general you will not be playing a ton of spells per turn so you are likely not affected too badly by these effects. Depending on how your local playgroup is trending at various times, Rule of Law effects can be very useful.
In the past, I have gone a little more towards life loss taxing effects with things like Polluted Bonds and Painful Quandary but they tend to come down a little later that I'd like usually. These are certainly playable in the deck and I may experiment with them again but at the moment I have taken them out.
Notable Combos
Beacon of Immortality + Vizkopa Guildmage: If you cast the Beacon of Immortality targeting yourself and activate the guildmage's second ability, this will likely kill the entire table if you have the highest life total.
Beacon of Immortality + Vito, Thorn of the Dusk Rose or Sanguine Bond: With either Vito or Sanguine Bond in play, you target yourself with Beacon of Immortality and kill one player with a lower life total than your own.
Axis of Mortality + Vito, Thorn of the Dusk Rose or Sanguine Bond: With either Vito or Sanguine Bond in play, during your upkeep if you have a low life total and exchange with a significantly higher life total you can potentially kill someone at the table depending on how much life you gain. A similar combo exists with Vizkopa Guildmage and Axis of Mortality but it hits everyone.
Axis of Mortality + Tainted Remedy: With these two cards in play simultaneously, if people have differing enough life totals you will be able to kill or seriously maim some of your opponents.
Beacon of Immortality + Tainted Remedy: With Tainted Remedy in play, you can target an opponent with Beacon of Immortality and kill them at instant speed.
Beacon of Immortality + Light of Promise: Depending on your life total, this can make a creature deal lethal combat damage. If the aura is on Liesa, you just need to be at 16 Life for a commander damage kill. If the aura is on another creature then that changes things but can still be lethal.
The above combos can all be enhanced by things like Tainted Sigil or Children of Korlis, which are other sources of life gain. For example, with Sanguine Bond + Tainted Sigil in play, target yourself with Beacon of Immortality to kill one player and then activate Tainted Sigil to kill another player.
Beacon of Immortality can be substituted in the above combos with cards like Exsanguinate or just a big enough lifelink creature depending on the board state as well.
Sanguine Bond + Exquisite Blood is a combo I have purposefully excluded from my deck. I used to see this a ton years ago and just got bored of seeing it. I would not begrudge others for running it but it is not for me.