Kefka, Ruler of Ruin

Flying
Whenever an opponent loses life during your turn, you draw that many cards.

Kefka, Court Mage

Whenever Kefka enters or attacks, each player discards a card. Then you draw a card for each card type among cards discarded this way.
{8}: Each opponent sacrifices a permanent of their choice. Transform Kefka. Activate only as a sorcery.

Kefka, Court Mage // Kefka, Ruler of Ruin

Cecil, Redeemed Paladin

Lifelink
Protect — Whenever Cecil attacks, other attacking creatures gain indestructible until end of turn.

Cecil, Dark Knight

Deathtouch
Darkness — Whenever Cecil deals damage, you lose that much life. Then if your life total is less than or equal to half your starting life total, untap Cecil and transform it.

Cecil, Dark Knight // Cecil, Redeemed Paladin

Venom, Lethal Protector

Menace, trample, haste
Whenever Venom attacks, you may sacrifice another creature. If you do, draw X cards, then you may put a permanent card with mana value X or less from your hand onto the battlefield, where X is the sacrificed creature's mana value.

Eddie Brock

When Eddie Brock enters, return target creature card with mana value 1 or less from your graveyard to the battlefield.
{3}{B}{R}{G}: Transform Eddie Brock. Activate only as a sorcery.

Eddie Brock // Venom, Lethal Protector

Aang, Destined Savior

Flying
Land creatures you control have vigilance.
At the beginning of combat on your turn, earthbend 2. (Target land you control becomes a 0/0 creature with haste that's still a land. Put two +1/+1 counters on it. When it dies or is exiled, return it to the battlefield tapped.)

Aang, at the Crossroads

Flying
When Aang enters, look at the top five cards of your library. You may put a creature card with mana value 4 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
When another creature you control leaves the battlefield, transform Aang at the beginning of the next upkeep.

Aang, at the Crossroads // Aang, Destined Savior

Aang, Master of Elements

Flying
Spells you cast cost {W}{U}{B}{R}{G} less to cast.
At the beginning of each upkeep, you may transform Aang, Master of Elements. If you do, you gain 4 life, draw four cards, put four +1/+1 counters on him, and he deals 4 damage to each opponent.

Avatar Aang

Flying, firebending 2
Whenever you waterbend, earthbend, firebend, or airbend, draw a card. Then if you've done all four this turn, transform Avatar Aang.

Avatar Aang // Aang, Master of Elements

Sephiroth, One-Winged Angel

Flying
Super Nova — As this creature transforms into Sephiroth, One-Winged Angel, you get an emblem with "Whenever a creature dies, target opponent loses 1 life and you gain 1 life."
Whenever Sephiroth attacks, you may sacrifice any number of other creatures. If you do, draw that many cards.

Sephiroth, Fabled SOLDIER

Whenever Sephiroth enters or attacks, you may sacrifice another creature. If you do, draw a card.
Whenever another creature dies, target opponent loses 1 life and you gain 1 life. If this is the fourth time this ability has resolved this turn, transform Sephiroth.

Sephiroth, Fabled SOLDIER // Sephiroth, One-Winged Angel

Beast Whisperer

Whenever you cast a creature spell, draw a card.

Trance Kuja, Fate Defied

Flare Star — If a Wizard you control would deal damage to a permanent or player, it deals double that damage instead.

Kuja, Genome Sorcerer

At the beginning of your end step, create a tapped 0/1 black Wizard creature token with "Whenever you cast a noncreature spell, this token deals 1 damage to each opponent." Then if you control four or more Wizards, transform Kuja.

Kuja, Genome Sorcerer // Trance Kuja, Fate Defied

Charnelhoard Wurm

Trample
Whenever this creature deals damage to an opponent, you may return target card from your graveyard to your hand.

Aang and La, Ocean's Fury

Reach, trample
Whenever Aang and La attack, put a +1/+1 counter on each tapped creature you control.

Aang, Swift Savior

Flash
Flying
When Aang enters, airbend up to one other target creature or spell. (Exile it. While it's exiled, its owner may cast it for {2} rather than its mana cost.)
Waterbend {8}: Transform Aang.

Aang, Swift Savior // Aang and La, Ocean's Fury

Phoenix, Warden of Fire

(As this Saga enters and after your draw step, add a lore counter.)
I, II — Rising Flames — Phoenix deals 2 damage to each opponent.
III — Flames of Rebirth — Return any number of target creature cards with total mana value 6 or less from your graveyard to the battlefield. Exile Phoenix, then return it to the battlefield (front face up).
Flying, lifelink

Joshua, Phoenix's Dominant

When Joshua enters, discard up to two cards, then draw that many cards.
{3}{R}{W}, {T}: Exile Joshua, then return it to the battlefield transformed under its owner's control. Activate only as a sorcery.

Joshua, Phoenix's Dominant // Phoenix, Warden of Fire

Ultimecia, Omnipotent

Menace (This creature can't be blocked except by two or more creatures.)
Time Compression — When this creature transforms into Ultimecia, Omnipotent, take an extra turn after this one.

Ultimecia, Time Sorceress

Whenever Ultimecia enters or attacks, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
At the beginning of your end step, you may pay {4}{U}{U}{B}{B} and exile eight cards from your graveyard. If you do, transform Ultimecia.

Ultimecia, Time Sorceress // Ultimecia, Omnipotent

Braska's Final Aeon

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I, II — Jecht Beam — Each opponent discards a card and you draw a card.
III — Ultimate Jecht Shot — Each opponent sacrifices two creatures of their choice.
Menace

Jecht, Reluctant Guardian

Menace
Whenever Jecht deals combat damage to a player, you may exile it, then return it to the battlefield transformed under its owner's control.

Jecht, Reluctant Guardian // Braska's Final Aeon

Ghost-Spider

Flying, vigilance, haste
Whenever you play a land from exile or cast a spell from exile, put a +1/+1 counter on Ghost-Spider.
Remove two counters from Ghost-Spider: Exile the top card of your library. You may play that card this turn.

Gwen Stacy

When Gwen Stacy enters, exile the top card of your library. You may play that card for as long as you control this creature.
{2}{U}{R}{W}: Transform Gwen Stacy. Activate only as a sorcery.

Gwen Stacy // Ghost-Spider

Moonmist

Transform all Humans. Prevent all combat damage that would be dealt this turn by creatures other than Werewolves and Wolves. (Only double-faced cards can be transformed.)

Avacyn, the Purifier

Flying
When this creature transforms into Avacyn, the Purifier, it deals 3 damage to each other creature and each opponent.

Archangel Avacyn

Flash
Flying, vigilance
When Archangel Avacyn enters, creatures you control gain indestructible until end of turn.
When a non-Angel creature you control dies, transform Archangel Avacyn at the beginning of the next upkeep.

Archangel Avacyn // Avacyn, the Purifier

Green Goblin

Flying, menace
Spells you cast from your graveyard cost {2} less to cast.
Goblin Formula — Each nonland card in your graveyard has mayhem. The mayhem cost is equal to its mana cost. (You may cast a card from your graveyard for its mayhem cost if you discarded it this turn. Timing rules still apply.)

Norman Osborn

Norman Osborn can't be blocked.
Whenever Norman Osborn deals combat damage to a player, he connives. (Draw a card, then discard a card. If you discarded a nonland card, put a +1/+1 counter on this creature.)
{1}{U}{B}{R}: Transform Norman Osborn. Activate only as a sorcery.

Norman Osborn // Green Goblin

Eternal Witness

When this creature enters, you may return target card from your graveyard to your hand.

Rona, Tolarian Obliterator

Trample
Whenever a source deals damage to Rona, that source's controller exiles a card from their hand at random. If it's a land card, you may put it onto the battlefield under your control. Otherwise, you may cast it without paying its mana cost.

Rona, Herald of Invasion

Whenever you cast a legendary spell, untap Rona.
{T}: Draw a card, then discard a card.
{5}{B/P}: Transform Rona. Activate only as a sorcery. ({B/P} can be paid with either {B} or 2 life.)