Flying
Whenever you cast a spell, return target permanent to its owner's hand.

Whenever a player casts a creature spell, that player sacrifices a permanent of their choice unless they pay .

Menace
: Spells you cast this turn that are black and/or red cost less to cast, where X is the amount of life you lost this turn. Activate only as a sorcery.

, , Sacrifice this artifact: Search your library for a land card, reveal it, put it into your hand, then shuffle.

Defender (This creature can't attack.)

During each of your turns, you may play a land and cast a permanent spell of each permanent type from your graveyard. (If a card has multiple permanent types, choose one as you play it.)

Living weapon (When this Equipment enters, create a 0/0 black Phyrexian Germ creature token, then attach this to it.)
Equipped creature gets +X/+X, where X is the number of creature cards in all graveyards.
Equip

Destroy target creature. If that creature dies this way, its controller creates two tokens that are copies of that creature, except their power is half that creature's power and their toughness is half that creature's toughness. Round up each time.

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after IV.)
I — Each player creates three tapped 1/1 white Warrior creature tokens. The tokens are goaded for as long as this Saga remains on the battlefield.
II, III — Put a +1/+1 counter on each Warrior creature.
IV — You may exile a nontoken creature you control. When you do, exile all Warriors.

+1: Each player discards a card. Each opponent who can't loses 3 life.
−3: Target creature gets -X/-X until end of turn, where X is the number of cards in your graveyard.
−7: You get an emblem with "At the beginning of combat on your turn, put target creature card from a graveyard onto the battlefield under your control. It gains haste."

Inquisition Agents — Whenever equipped creature attacks, create a 2/2 white Astartes Warrior creature token with vigilance that's attacking. Then attacking creatures gain menace until end of turn.
Equip (: Attach to target creature you control. Equip only as a sorcery.)

At the beginning of each player's draw step, if this artifact is untapped, that player draws an additional card.

+1: Up to one target creature gets -2/-1 until your next turn.
−2: Mill two cards, then you may return a creature card from your graveyard to your hand.
−7: You get an emblem with "At the beginning of your end step, create X 2/2 black Zombie creature tokens, where X is two plus the number of Zombies you control."

First strike, trample
When this creature enters, you may search your library for up to two artifact, creature, and/or enchantment cards with mana value 1 or less, reveal them, put them into your hand, then shuffle.

Commander ninjutsu (, Return an unblocked attacker you control to hand: Put this card onto the battlefield from your hand or the command zone tapped and attacking.)
Whenever a Ninja you control deals combat damage to a player, reveal the top card of your library and put that card into your hand. Each opponent loses life equal to that card's mana value.

Enchant creature you control
When enchanted creature dies, return it to the battlefield under your control, then return this card to the battlefield transformed under your control.

Haste
Echo (At the beginning of your upkeep, if this came under your control since the beginning of your last upkeep, sacrifice it unless you pay its echo cost.)
When this creature enters, destroy target land.

Flying
Creatures you control have "Whenever this creature becomes the target of a spell or ability for the first time each turn, counter that spell or ability."

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)