Past Lives
Enchantment — Aura
Enchant creature you control
Imprint — When Past Lives enters, exile a creature card with mana value less than enchanted creature's mana value from your graveyard.
If enchanted creature would die, put it on the bottom of your library instead. If you do, put the exiled card onto the battlefield, exile Past Lives, then return Past Lives to the battlefield attached to that creature.

Days of our Lives
Enchantment (M)
When Days of our Lives enters, create a 1/1 white human soldier, a 1/1 blue human wizard, a 1/1 red human mercenary, a 1/1 black human rogue and a 1/1 green human druid creature token.
Whenever one of the following occurs that has not occured before, put a Soap counter on Days of our Lives ─
• a creature connives
• a creature is soulbonded
• a creature is copied
• a creature returns to the battlefield from a graveyard
• a creature fights
At the beginning of your upkeep, if there are five Soap counters on Days of our Lives, you win the game.

Daybreak

Sorcery
After this main phase, target player takes an additional upkeep step. (Your turn then proceeds as normal.)
Draw a card.
Every sunrise a reset, every dawn an opportunity.

Break the Stallion
Sorcery (R)
Choose one ─
• Search your library for a creature card with Saddle, reveal it and put it into your hand.
• Put a creature card with Saddle from your hand onto the battlefield. It gains haste. At the beginning of the end step, sacrifice it.

Sea-Trench Megalodon
Creature — Shark Leviathan
At the beginning of your end step, put the bottom card of your library in your graveyard. If that card is a creature card with mutate, you may cast it without paying its mana cost if that spell targets Sea-Trench Megalodon.
Sea-Trench Megalodon can't attack or block unless it has mutated three or more times.
4/4

Trench Warfare
Enchantment
At the beginning of your end step, put a +1/+1 counter on each untapped creature you control, and remove all +1/+1 counters from each tapped creature you control.

Principles of War
Enchantment (R)
At the beginning of your combat phase, choose one that hasn't been chosen ─
• Surround ─ If you are attacking in greater numbers, deal 6 damage to target creature.
• Attack ─ If you are attacking with equal numbers, creatures you control get +3/+0 until end of turn.
• Divide ─ If you are attacking with inferior numbers, defending player can't block.
• Surprise ─ Put a creature card from your hand onto the battlefield tapped and attacking.

Principle Mckeon
Legendary Creature ─ Human Wizard (M)
Your opponents can't gain life, create tokens or cast historic spells.
2/5
Strixhaven's dark side shows in the detention hall, but it's not the students.

Betray Principles
Sorcery
As an additional cost to cast this spell, sacrifice an enchantment.
Search your library for an artifact card, put it onto the battlefield, then shuffle.

Last Man Standing
Enchantment ─ Aura (R)
Enchant creature
If enchanted creature is the only creature you control it gets +7/+7 and gains defender and indestructible.

Man versus Nature

Sorcery
Choose one -

• Man - Destroy all nonartifact creatures
• Nature - Destroy all artifacts.

Unnatural Genesis
Sorcery
Return target creature card from your graveyard to the battlefield and exile another target creature card from your graveyard. The creature card on the battlefield gains the abilities of the exiled card.

Begone, Thought
Instant
As an additional cost to cast this spell, discard X cards.
The next X times target opponent would draw a card this turn, they discard a card instead.

Begone, Foul Demon!
Sorcery (U)
Exile target creature you own but don't control.
Draw a card.

Foil Foul Play
Enchantment (R)
Whenever you investigate, counter target spell an opponent controls.

Feels like it should be an "up to one" or "target spell an opponent controls" to avoid it triggering while you have the only spell.

Foil Treatment
Instant
Target spell or permanent becomes all colors and legendary. It gains "When this permanent is put into a graveyard from the battlefield, create a Treasure token."