The Celestus

If it's neither day nor night, it becomes day as The Celestus enters.
{T}: Add one mana of any color.
{3}, {T}: If it's night, it becomes day. Otherwise, it becomes night. Activate only as a sorcery.
Whenever day becomes night or night becomes day, you gain 1 life. You may draw a card. If you do, discard a card.

Olivia, Crimson Bride

Flying, haste
Whenever Olivia, Crimson Bride attacks, return target creature card from your graveyard to the battlefield tapped and attacking. It gains "When you don't control a legendary Vampire, exile this creature."

Olivia's Attendants

Menace
Whenever Olivia's Attendants deals damage, create that many Blood tokens. (They're artifacts with "{1}, {T}, Discard a card, Sacrifice this artifact: Draw a card.")
{2}{R}: Olivia's Attendants deals 1 damage to any target.

Fearsome Werewolf

Menace (This creature can't be blocked except by two or more creatures.)
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Fearful Villager

Menace (This creature can't be blocked except by two or more creatures.)
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Fearful Villager // Fearsome Werewolf

Ballista Wielder

{2}{R}: Ballista Wielder deals 1 damage to any target. A creature dealt damage this way can't block this turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Ballista Watcher

{2}{R}, {T}: Ballista Watcher deals 1 damage to any target.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Ballista Watcher // Ballista Wielder

Olivia's Bloodsworn

Flying
Olivia's Bloodsworn can't block.
{R}: Target Vampire gains haste until end of turn.

Olivia's Dragoon

Discard a card: Olivia's Dragoon gains flying until end of turn.

Olivia Voldaren

Flying
{1}{R}: Olivia Voldaren deals 1 damage to another target creature. That creature becomes a Vampire in addition to its other types. Put a +1/+1 counter on Olivia Voldaren.
{3}{B}{B}: Gain control of target Vampire for as long as you control Olivia Voldaren.

Vampire Noble

Brimstone Vandal

Menace (This creature can't be blocked except by two or more creatures.)
If it's neither day nor night, it becomes day as Brimstone Vandal enters.
Whenever day becomes night or night becomes day, Brimstone Vandal deals 1 damage to each opponent.

Obsessive Astronomer

If it's neither day nor night, it becomes day as Obsessive Astronomer enters.
Whenever day becomes night or night becomes day, discard up to two cards, then draw that many cards.

Deadly Dancer

Trample
When this creature transforms into Deadly Dancer, add {R}{R}. Until end of turn, you don't lose this mana as steps and phases end.
{R}{R}: Deadly Dancer and another target creature each get +1/+0 until end of turn.

Alluring Suitor

When you attack with exactly two creatures, transform Alluring Suitor.

Alluring Suitor // Deadly Dancer

Olivia's Midnight Ambush

Target creature gets -2/-2 until end of turn. If it's night, that creature gets -13/-13 until end of turn instead.

Sunstreak Phoenix

Flying
If it's neither day nor night, it becomes day as Sunstreak Phoenix enters.
Whenever day becomes night or night becomes day, you may pay {1}{R}. If you do, return Sunstreak Phoenix from your graveyard to the battlefield tapped.

Leeching Lurker

Lifelink
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Curse of Leeches

Enchant player
As this permanent transforms into Curse of Leeches, attach it to a player.
At the beginning of enchanted player's upkeep, they lose 1 life and you gain 1 life.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Curse of Leeches // Leeching Lurker

Into the Night

It becomes night. Discard any number of cards, then draw that many cards plus one.

Baneclaw Marauder

Whenever Baneclaw Marauder becomes blocked, each creature blocking it gets -1/-1 until end of turn.
Whenever a creature blocking Baneclaw Marauder dies, that creature's controller loses 1 life.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Baneblade Scoundrel

Whenever Baneblade Scoundrel becomes blocked, each creature blocking it gets -1/-1 until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Baneblade Scoundrel // Baneclaw Marauder

Fangblade Eviscerator

{1}{R}: Fangblade Eviscerator gets +1/+0 and gains first strike until end of turn.
{4}{R}: Creatures you control get +2/+0 until end of turn.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Fangblade Brigand

{1}{R}: Fangblade Brigand gets +1/+0 and gains first strike until end of turn.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)