He's not obviously powerful: Mono-white is usually considered the weakest Commander color identity, and Heliod appears slow and clunky. So you won't immediately be seen as a threat the way someone who starts the game with, say, Purphuros, or one of the older, popular multicolor generals in the command zone. But he actually plays to mono-white's strengths in a number of ways. See how...
Small threats that get bigger win games. White gets little credit for how its Crusade effects (including double strike granters) can quickly turn armies of small men into fearsome ones. Crusade effects get exponentially better when you can easily pump out creatures without costing you cards. The presence of two-mana and three-mana creature make it easy to use all of your mana each to turn to build an army. Besides the familiar suite of Anthem-type enchantments, the deck plays a number of "hidden Crusades" like Celestial Ancient and True Conviction. Cathar's Crusade is especially scary because it is a true exponential effect when Heliod is on the field.
You get to pack your deck with mass creature removal. Heliod shrugs off your own multitude of Wrath effects: He's indestructible and can't be dealt with easily unless your opponents draw a sweeper like All is Dust; Hallowed Burial and Terminus only remove him if he's a creature, etc. What's more, he quickly builds a board presence back up again by filling the battlefield with new Cleric devotees.
Lots of synergies. From attacking with an army with Archangel of Thune and Path of Bravery in play, to Ajani's Chosen giving you a 2/2 Cat for each Cleric-enchantment token Heliod makes, to tapping Serra's Sanctum to get a W for each of Heliod's tokens and grow the army even faster turn by turn, to all the tricks Master Apothecary allows (not just a huge boost to devotion, but also thanks to Heliod's vigilance, the ability to launch alpha strikes with your whole Cleric team, and still easily protect a few members of the team who get lethally blocked, or protect yourself from counter-attacks.)
It's not clear to me yet, since I haven't gotten my (digital) hands on a Heliod, what direction the deck should evolve in given how it plays in practice. There are plenty of Crusades and Wraths that aren't in the deck but could be (all the way down to Angelic Voices and Kirtar's Wrath). Maybe I want Heliod to have devotion less often, to protect it from tucking and exiling effects that target creatures, or maybe I find he can protect himself enough that I want more devotion enablers. (Opal Guardian?) Maybe I want to play up the enchantment sub-theme, or the life-gain sub-theme, or the tokens theme. Maybe I want to go in a pillow-fort direction with Ghostly Prison or Sphere of Safety. Maybe more disruptive creatures are needed to build up to a win (Ethersworn Canonist, True Believer, Mangara of Corondor, Peacekeeper). I won't know until I get to test him out... or until you do.
You're playing a lot of creatures that don't actually do anything for you. While Baneslayer Angel is a beast in 20 life formats, she's pretty mediocre here. You need to focus on the token creation and control sub-theme much more than you presently are. Heliod is on the weaker side of commanders (though still better than most W commanders). That means you have to make the deck as distilled as possible. I'd abandon the enchantment theme. Just the rawest, most efficient means of accomplishing your goals.
You need more "army-in-a-can" type cards. Myr Battlesphere, Cloudgoat Ranger, etc. It's just there to make more tokens anyways. Gives you more room for actually winning the game. Battle Screech is way too low impact. The other two Elspeth cards are amazing as is Ajani Goldmane. Mobilization, Sacred Mesa are both extremely good at what Heliod does.
You should try to get Snow lands and include Extraplanar Lens. This deck is extremely mana hungry, so you should probably have a stronger ramp package in the first place.
"The distance between genius and insanity... Is measured only by success."
-Elliot Carver, Tomorrow Never Dies
"If violence isn't solving it, you're obviously not using enough!"
-Me
A kid at my local gameshop wanted to break a twenty.
"You got 2 tens?" he asked me.
"No, but I probably got 3 fives." I replied.
"Perfect!"
"You might want to check your math there."
I wouldn't bother with the Vesuva like lands. This deck is slow enough without a million more ETBT lands. I don't think you need the fetches if you include some decent artifact ramp. You will never in your life successfully Strip lock somebody, so I don't think Crucible does anything for you. I would add Strip Mine and its ilk as sometimes you want that Gaea's Cradle or Bazaar of Baghdad dead. You don't need Rings of Brighthearth at all. Idyllic Tutor isn't really worth it if you cut down on the enchantment package (which you should). Academy Rector, on the other hand, can power out a very early True Conviction. Include High Market.
He's not obviously powerful: Mono-white is usually considered the weakest Commander color identity, and Heliod appears slow and clunky. So you won't immediately be seen as a threat the way someone who starts the game with, say, Purphuros, or one of the older, popular multicolor generals in the command zone. But he actually plays to mono-white's strengths in a number of ways. See how...
Small threats that get bigger win games. White gets little credit for how its Crusade effects (including double strike granters) can quickly turn armies of small men into fearsome ones. Crusade effects get exponentially better when you can easily pump out creatures without costing you cards. The presence of two-mana and three-mana creature make it easy to use all of your mana each to turn to build an army. Besides the familiar suite of Anthem-type enchantments, the deck plays a number of "hidden Crusades" like Celestial Ancient and True Conviction. Cathar's Crusade is especially scary because it is a true exponential effect when Heliod is on the field.
You get to pack your deck with mass creature removal. Heliod shrugs off your own multitude of Wrath effects: He's indestructible and can't be dealt with easily unless your opponents draw a sweeper like All is Dust; Hallowed Burial and Terminus only remove him if he's a creature, etc. What's more, he quickly builds a board presence back up again by filling the battlefield with new Cleric devotees.
Disrupt your opponents. Plenty of white creatures disrupt opposing strategies. An opponent hoping to combo with Ghave, Guru of Spores by repeatedly making and sacrificing Saprolings, for example, runs into trouble if you have Jubilation Angel, Suture Priest, Linvala, Keeper of Silence, or (possibly) Samurai of the Pale Curtain out.
Lots of synergies. From attacking with an army with Archangel of Thune and Path of Bravery in play, to Ajani's Chosen giving you a 2/2 Cat for each Cleric-enchantment token Heliod makes, to tapping Serra's Sanctum to get a W for each of Heliod's tokens and grow the army even faster turn by turn, to all the tricks Master Apothecary allows (not just a huge boost to devotion, but also thanks to Heliod's vigilance, the ability to launch alpha strikes with your whole Cleric team, and still easily protect a few members of the team who get lethally blocked, or protect yourself from counter-attacks.)
1 Heliod, God of the Sun
Creatures:29
1 Serra Ascendant
1 Soul Warden
1 Soul's Attendant
1 Weathered Wayfarer
1 Auriok Champion
1 Grand Abolisher
1 Knight of the White Orchid
1 Leonin Relic-Warder
1 Samurai of the Pale Curtain
1 Suture Priest
1 Aven Mindcensor
1 Master Apothecary
1 Mirran Crusader
1 Silverblade Paladin
1 Ajani's Chosen
1 Angel of Jubilation
1 Celestial Crusader
1 Dawn Elemental
1 Emeria Angel
1 Hero of Bladehold
1 Linvala, Keeper of Silence
1 Archangel of Thune
1 Baneslayer Angel
1 Celestial Ancient
1 Geist-Honored Monk
1 Crovax, Ascendant Hero
1 Sun Titan
1 Elesh Norn, Grand Cenobite
1 Eternal Dragon
1 Land Tax
1 Honor of the Pure
1 Rest in Peace
1 Seal of Cleansing
1 Aura of Silence
1 Divine Sacrament
1 Glorious Anthem
1 Path of Bravery
1 Prison Term
1 Spear of Heliod
1 Endless Horizons
1 Faith's Fetters
1 Marshal's Anthem
1 Cathars' Crusade
1 True Conviction
Other spells:17
1 Enlightened Tutor
1 Sol Ring
1 Swords to Plowshares
1 Tithe
1 Gift of Estates
1 Martial Coup
1 Oblation
1 Battle Screech
1 Day of Judgment
1 Wrath of God
1 Gauntlet of Power
1 Hallowed Burial
1 Rout
1 Austere Command
1 Caged Sun
1 Elspeth, Sun's Champion
1 Spectral Procession
1 Emeria, the Sky Ruin
1 Kor Haven
1 Mistveil Plains
1 Nykthos, Shrine to Nyx
31 Plains
1 Secluded Steppe
1 Serra's Sanctum
1 Temple of the False God
How this breaks down, strategically:
1 Honor of the Pure
1 Divine Sacrament
1 Glorious Anthem
1 Path of Bravery
1 Spear of Heliod
1 Marshal's Anthem
1 Cathars' Crusade
1 Gauntlet of Power
1 Caged Sun
1 True Conviction
1 Celestial Crusader
1 Archangel of Thune
1 Celestial Ancient
1 Crovax, Ascendant Hero
1 Elesh Norn, Grand Cenobite
Enchantment lovers:
1 Celestial Ancient
1 Ajani's Chosen
1 Enlightened Tutor
1 Serra's Sanctum
1 Heliod, God of the Sun
1 Ajani's Chosen
1 Battle Screech
1 Geist-Honored Monk
1 Spectral Procession
1 Elspeth, Sun's Champion
1 Emeria Angel
1 Hero of Bladehold
1 Martial Coup
Disruptive dudes:
1 Grand Abolisher
1 Leonin Relic-Warder
1 Samurai of the Pale Curtain
1 Suture Priest
1 Aven Mindcensor
1 Angel of Jubilation
1 Linvala, Keeper of Silence
1 Crovax, Ascendant Hero
1 Elesh Norn, Grand Cenobite
Mana building:
1 Weathered Wayfarer
1 Knight of the White Orchid
1 Eternal Dragon
1 Enlightened Tutor
1 Land Tax
1 Sol Ring
1 Tithe
1 Gift of Estates
1 Endless Horizons
1 Gauntlet of Power
1 Caged Sun
1 Serra's Sanctum
1 Nykthos, Shrine to Nyx
1 Martial Coup
1 Day of Judgment
1 Wrath of God
1 Hallowed Burial
1 Rout
1 Austere Command
1 Elspeth, Sun's Champion
It's not clear to me yet, since I haven't gotten my (digital) hands on a Heliod, what direction the deck should evolve in given how it plays in practice. There are plenty of Crusades and Wraths that aren't in the deck but could be (all the way down to Angelic Voices and Kirtar's Wrath). Maybe I want Heliod to have devotion less often, to protect it from tucking and exiling effects that target creatures, or maybe I find he can protect himself enough that I want more devotion enablers. (Opal Guardian?) Maybe I want to play up the enchantment sub-theme, or the life-gain sub-theme, or the tokens theme. Maybe I want to go in a pillow-fort direction with Ghostly Prison or Sphere of Safety. Maybe more disruptive creatures are needed to build up to a win (Ethersworn Canonist, True Believer, Mangara of Corondor, Peacekeeper). I won't know until I get to test him out... or until you do.
You need more "army-in-a-can" type cards. Myr Battlesphere, Cloudgoat Ranger, etc. It's just there to make more tokens anyways. Gives you more room for actually winning the game. Battle Screech is way too low impact. The other two Elspeth cards are amazing as is Ajani Goldmane. Mobilization, Sacred Mesa are both extremely good at what Heliod does.
You should try to get Snow lands and include Extraplanar Lens. This deck is extremely mana hungry, so you should probably have a stronger ramp package in the first place.
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Strongly recommended are 4 white fetches, Crucible of Worlds, Strip Mine, Wasteland (or Tectonic Edge if you can't afford a wasteland), Maze of Ith, Sword of Feast and Famine, Ancient Tomb, Pearl Medallion, Vesuva, Thespian's Stage, and Idyllic Tutor.
I'd recommend switching to Snow-Covered Plains and adding Extraplanar Lens, cuz 3 mana doublers is better than 2.
Also think about Heartstone.
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The EPIC EDHWUBRG
Sun Quan Aggro1U
Animar GoodstuffRUG
Horobi MBCB
Medomai NerfWU
Saffi EriksdotterGW
Zur (CF)WUB
-Elliot Carver, Tomorrow Never Dies
"If violence isn't solving it, you're obviously not using enough!"
-Me
A kid at my local gameshop wanted to break a twenty.
"You got 2 tens?" he asked me.
"No, but I probably got 3 fives." I replied.
"Perfect!"
"You might want to check your math there."
My Blog About It
Heartstone only applies to creatures. So unless, you have devotion 5, it will be useless
-Calvin & Hobbes