Fired UpxR
Enchantment
Fired Up enters the battlefield with X fire counters on it.
Spells you cast with converted mana cost equal to the number of fire counters on this can't be countered. If that spell would deal damage, that damage can't be prevented.
Second Fire
Enchantment
If a source would deal exactly 1 damage, it deals 2 damage instead.
Barrier of Light
Enchantment
As long as you control a creature with hexproof from black, all creatures you control have hexproof from black. The same is true for hexproof from red.
Damage done to your creatures from red or black sources is reduced by 1.
Since Dominaria introduced Hexproof from color and protection from color is much less used, I opted for hexproof + damage reduction.
Gate to the Afterlife
Enchantment
Whenever a creature you control dies, create a 1/1 white spirit token with flying.
At the beginning of your upkeep, you gain 1 life for each spirit token you control.
Odd or Even
Sorcery
Choose one:
Destroy all nonland permanents with an even converted mana cost
Destroy all nonland permanents with an odd converted mana cost
The One Circle
Enchantment
If a source would deal exactly 1 damage, it deals no damage instead.
The name is a pun with Circle of Protection.
Protection of Lights
Enchantment
If a source would deal damage to a creature you control, prevent that damage if that source shares a color with that creature.
Serra, The Holy Protector
Legendary Planeswalker — Serra
Starting Loyalty: 4
+1: Until your next turn, all damage that would be dealt to you is prevented.
-1: You gain 1 life for each creature you control.
-7: You get an emblem “At the beginning of your upkeep, your life total becomes 20.”
My first attempt at making a planeswalker.
Shield of Light
Enchantment
If a source that shares a color with a permanent you control would deal damage to you, prevent 1 of that damage.
Trinity Shield
Enchantment
If a source would deal exactly 3 damage to you, a creature or a planeswalker you control, it deals 1 damage instead.
White Aura
Enchantment
The next time a source of your choice would deal damage to you, prevent that damage and sacrifice White Aura. You gain life equal to the damage prevented this way.
It could be expanded to damage that would be dealt to planeswalker and creatures.
The Darkness
Enchantment
Whenever a creature dies, all lands become swamps until end of turn.
The black Blood Moon.
Death Web
Enchantment
When Death Web enters the battlefield, remove all counters from all creatures.
If one or more counters would be placed on a creature, destroy it instead.
Fear the Night
Enchantment
Whenever a creature dies, all creatures get -1/-1 until end of turn.
Eat the Ashes
Sorcery
Destroy target nonland permanent. You gain 3 life.
Killing Blow
Instant
Put target creature and all permanents attached to it in its owner's graveyard.
Mirror Mage
Creature - Wizard
When a spell or ability targets Mirror Mage, that spell or ability's controller may copy it. That player may choose new targets for the copy. The copy can't target Mirror Mage.
2/2
Soul Trade
Sorcery
Exile target creature card from a graveyard. Draw cards equal to its power.
Book of Greed
Artifact
If a player would draw a card and has no cards in their hand, they draw two cards instead.
Goblet of Life
Artifact
When Goblet of Life enters the battlefield, choose a color.
At the beginning of your upkeep, you gain X life, where X is the number of permanents you control of the chosen color.
Wheel of Pain
Artifact
At the beginning of each opponent's upkeep, Wheel of Pain deals X damage to him, where X is the difference in cards between cards in your hand and cards in their hand.
There's a lot here, so I'll just address what I can.
Serra is a little weak for a planeswalker of her reputation. Her +1 is alright. It's essentially a worse version of Gideon Jura's +2, except that Serra is much squishier and can't protect your other planeswalkers. My main issue is that her abilities don't have much synergy. Her ultimate doesn't win you the game by itself, but it renders all of your lifegain effects useless. 20 is pocket change for a real lifegain deck, after all. She would make more sense if she had some way to protect herself, but as it stands she's a 4 CMC fog.
Fired Up is super narrow. Combo decks can take advantage of this, I suppose, but even paying 3 mana for it sounds like a stretch.
Second Fire is a cool card. Definitely a red take on Honor of the Pure.
Barrier of Light feels like a throwback with modern terminology.
Gate to the Afterlife is seriously oppressive. It should probably just trigger from nontoken or non-spirit creatures to prevent it from just being an infinite sac outlet.
Protection of Lights is another super-narrow hoser. Two mono-white decks pulling this out in game 2 sounds super boring. The same goes for Shield of Light.
I honestly can't see a situation in which I would play Trinity Shield.
The White Aura is formatted wrong. I don't know how this replacement ability should be spelled out, but definitely not the same way as you'd put on and instant or sorcery.
Fired Up, this is interesting, though could be worded better. "Spells you control with converted mana cost equal to the number of fire counters on fired up can't be countered by spells or abilities. Damage from sources with converted mana cost equal to the number of fire counters on fired up can't be prevented." It need to be spells or abilities so the game rules can still counter them. The change to making them two abilities means your permanent can benefit from the damage part.
Second Fire, this seems so perfect the only reason I can think of as for why it isn't already a card is because it's too strong. It looks fine though.
Barrier of Light, a nice new take on Righteous War. It feels weird only granting hexproof if you have it but always preventing damage.
Gate to the Afterlife, this needs either non-spirit or nontoken.
Odd or Even, probably need to cost five or only hit creature.
The one Circle, it's interesting but I can't see this ever being played.
Protection of Lights, this is far too oppressive.
Serra is disjointed and weak. She needs a unifying theme and to be powered up.
Shield of Light, I've always liked the Spheres of protection.
Trinity Shield, expensive hate against legacy burn?
White Aura, this needs to either be an activated ability or drop the your choice. You could probably keep it the awkward replacement effect that sacs mid resolution but that is confusing.
The Darkness, seems both oppressive and useless. Such designs are troublesome.
Death Web, this really depends on it's environment to see if it's ok or not.
Fear the Night, I like this but it has the flavor of a spreading plague.
Eat the Ashes, very strong, probably fine.
Killing Blow, there are problems with terminology here. It's obvious what you want to do but it's not something the game does. Probably too strong as an instant.
Mirror Mage, this is weird, possibly bad. I'm certain you want to copy not the spells controller, it's free removal. Also problems with auras.
Soul Trade, interesting, possibly underpowered.
Book of Greed, an interesting take on howling mine. I don't think it's good but it's interesting.
Goblet of Life, very underwhelming. Should drop cost.
Protection of Lights v2
Enchantment
If damage would be dealt to a creature by a source that shares a color with it, prevent that damage.
Made it symmetrical.
Serra, Protector of Realms
Legendary Planeswalker — Serra
Starting Loyalty: 4
+1: Target creature you control gets +2/+2, flying and vigilance until end of turn.
+1: You gain 2 life for each creature you control.
-7: You get an emblem “At the beginning of your upkeep, create a 5/5 white angel token with first strike, vigilance and flying”.
Reworked all abilities.
Fear the Night. Fear Death probably fits better with that ability.
Mirror Mage. Probably should specify "Instant, sorcery or ability".
The Darkness. In the right deck this would essentially prevent your opponent from playing anything.
Painful DeathBB
Enchantment
Whenever a creature dies, its controller loses 1 life.
Enchantment
Fired Up enters the battlefield with X fire counters on it.
Spells you cast with converted mana cost equal to the number of fire counters on this can't be countered. If that spell would deal damage, that damage can't be prevented.
Second Fire
Enchantment
If a source would deal exactly 1 damage, it deals 2 damage instead.
Barrier of Light
Enchantment
As long as you control a creature with hexproof from black, all creatures you control have hexproof from black. The same is true for hexproof from red.
Damage done to your creatures from red or black sources is reduced by 1.
Since Dominaria introduced Hexproof from color and protection from color is much less used, I opted for hexproof + damage reduction.
Gate to the Afterlife
Enchantment
Whenever a creature you control dies, create a 1/1 white spirit token with flying.
At the beginning of your upkeep, you gain 1 life for each spirit token you control.
Odd or Even
Sorcery
Choose one:
Destroy all nonland permanents with an even converted mana cost
Destroy all nonland permanents with an odd converted mana cost
The One Circle
Enchantment
If a source would deal exactly 1 damage, it deals no damage instead.
The name is a pun with Circle of Protection.
Protection of Lights
Enchantment
If a source would deal damage to a creature you control, prevent that damage if that source shares a color with that creature.
Serra, The Holy Protector
Legendary Planeswalker — Serra
Starting Loyalty: 4
+1: Until your next turn, all damage that would be dealt to you is prevented.
-1: You gain 1 life for each creature you control.
-7: You get an emblem “At the beginning of your upkeep, your life total becomes 20.”
My first attempt at making a planeswalker.
Shield of Light
Enchantment
If a source that shares a color with a permanent you control would deal damage to you, prevent 1 of that damage.
Trinity Shield
Enchantment
If a source would deal exactly 3 damage to you, a creature or a planeswalker you control, it deals 1 damage instead.
White Aura
Enchantment
The next time a source of your choice would deal damage to you, prevent that damage and sacrifice White Aura. You gain life equal to the damage prevented this way.
It could be expanded to damage that would be dealt to planeswalker and creatures.
The Darkness
Enchantment
Whenever a creature dies, all lands become swamps until end of turn.
The black Blood Moon.
Death Web
Enchantment
When Death Web enters the battlefield, remove all counters from all creatures.
If one or more counters would be placed on a creature, destroy it instead.
Fear the Night
Enchantment
Whenever a creature dies, all creatures get -1/-1 until end of turn.
Eat the Ashes
Sorcery
Destroy target nonland permanent. You gain 3 life.
Killing Blow
Instant
Put target creature and all permanents attached to it in its owner's graveyard.
Mirror Mage
Creature - Wizard
When a spell or ability targets Mirror Mage, that spell or ability's controller may copy it. That player may choose new targets for the copy. The copy can't target Mirror Mage.
2/2
Soul Trade
Sorcery
Exile target creature card from a graveyard. Draw cards equal to its power.
Book of Greed
Artifact
If a player would draw a card and has no cards in their hand, they draw two cards instead.
Goblet of Life
Artifact
When Goblet of Life enters the battlefield, choose a color.
At the beginning of your upkeep, you gain X life, where X is the number of permanents you control of the chosen color.
Wheel of Pain
Artifact
At the beginning of each opponent's upkeep, Wheel of Pain deals X damage to him, where X is the difference in cards between cards in your hand and cards in their hand.
Serra is a little weak for a planeswalker of her reputation. Her +1 is alright. It's essentially a worse version of Gideon Jura's +2, except that Serra is much squishier and can't protect your other planeswalkers. My main issue is that her abilities don't have much synergy. Her ultimate doesn't win you the game by itself, but it renders all of your lifegain effects useless. 20 is pocket change for a real lifegain deck, after all. She would make more sense if she had some way to protect herself, but as it stands she's a 4 CMC fog.
Fired Up is super narrow. Combo decks can take advantage of this, I suppose, but even paying 3 mana for it sounds like a stretch.
Second Fire is a cool card. Definitely a red take on Honor of the Pure.
Barrier of Light feels like a throwback with modern terminology.
Gate to the Afterlife is seriously oppressive. It should probably just trigger from nontoken or non-spirit creatures to prevent it from just being an infinite sac outlet.
Odd or Even is, uh, Hit or Miss.
The One Circle is a Grapeshot hoser. I approve.
Protection of Lights is another super-narrow hoser. Two mono-white decks pulling this out in game 2 sounds super boring. The same goes for Shield of Light.
I honestly can't see a situation in which I would play Trinity Shield.
The White Aura is formatted wrong. I don't know how this replacement ability should be spelled out, but definitely not the same way as you'd put on and instant or sorcery.
Second Fire, this seems so perfect the only reason I can think of as for why it isn't already a card is because it's too strong. It looks fine though.
Barrier of Light, a nice new take on Righteous War. It feels weird only granting hexproof if you have it but always preventing damage.
Gate to the Afterlife, this needs either non-spirit or nontoken.
Odd or Even, probably need to cost five or only hit creature.
The one Circle, it's interesting but I can't see this ever being played.
Protection of Lights, this is far too oppressive.
Serra is disjointed and weak. She needs a unifying theme and to be powered up.
Shield of Light, I've always liked the Spheres of protection.
Trinity Shield, expensive hate against legacy burn?
White Aura, this needs to either be an activated ability or drop the your choice. You could probably keep it the awkward replacement effect that sacs mid resolution but that is confusing.
The Darkness, seems both oppressive and useless. Such designs are troublesome.
Death Web, this really depends on it's environment to see if it's ok or not.
Fear the Night, I like this but it has the flavor of a spreading plague.
Eat the Ashes, very strong, probably fine.
Killing Blow, there are problems with terminology here. It's obvious what you want to do but it's not something the game does. Probably too strong as an instant.
Mirror Mage, this is weird, possibly bad. I'm certain you want to copy not the spells controller, it's free removal. Also problems with auras.
Soul Trade, interesting, possibly underpowered.
Book of Greed, an interesting take on howling mine. I don't think it's good but it's interesting.
Goblet of Life, very underwhelming. Should drop cost.
Wheel of Pain, I think Dark Suspicions is over costed
Enchantment
If damage would be dealt to a creature by a source that shares a color with it, prevent that damage.
Made it symmetrical.
Serra, Protector of Realms
Legendary Planeswalker — Serra
Starting Loyalty: 4
+1: Target creature you control gets +2/+2, flying and vigilance until end of turn.
+1: You gain 2 life for each creature you control.
-7: You get an emblem “At the beginning of your upkeep, create a 5/5 white angel token with first strike, vigilance and flying”.
Reworked all abilities.
Fear the Night. Fear Death probably fits better with that ability.
Mirror Mage. Probably should specify "Instant, sorcery or ability".
The Darkness. In the right deck this would essentially prevent your opponent from playing anything.
Painful Death BB
Enchantment
Whenever a creature dies, its controller loses 1 life.