Cronus Stone UUU
Legendary Artifact UUUUT, Sacrifice Cronus Stone: Target player takes an extra turn after this. Activate this ability only during your turn.
Prometheus Stone RRR
Legendary Artifact RRRRt, Sacrifice Prometheus Stone: Deal 9 damage divided as you choose to any number of target creatures and/or Planeswalkers. Activate this ability only during your turn.
Haden Stone BBB
Legendary Artifact BBBBt, Sacrifice Haden Stone: Destroy target creature then put a creature card from a graveyard onto the battlefield under your control. Activate this ability only during your turn.
Emergence Stone GGG
Legendary Artifact GGGGt, Sacrifice Emergence Stone: Search your library, hand, or from outside the game for a Green creature card you own and put it onto the battlefield with a +1/+1 counter on it for each basic land you control.If you search your library in this way, shuffle it. Activate this ability only during your turn.
Lustration Stone WWW
Legendary Artifact WWWWt, Sacrifice Lustration Stone: Choose a nonland permanent card type. Each player sacrifices all nonland cards except for cards of the chosen type. Activate this ability only during your turn.
Blue - Probably needs to exile itself, artifacts are fairly easy to recur, especially in blue.
Green - Templating doesn't use "sideboard" its something more like "you own from outside the game". Also needs "If you search your library in this way, shuffle it."
White - Should say "permanent" instead of "card". If you choose Instant or Sorcery everyone just sacs everything, and also technically the way its worded you'd have to sacrifice Instants or Sorceries, which isn't a thing.
Other than that, I guess they just seem a bit weak. For 3 mana they don't have any immediate effect, and you're fairly restricted on how/when you can sac them, the effects are a little underwhelming. The red one seems about fine for 7 total mana, blue/black/white seem a bit overpriced for that effect, and the green one is maybe a bit too good given the +1/+1 counters. If it was for each basic land "type" instead of each land itself that seems reasonable.
Overall though, they don't seem like Power Stones to me. I always think of cards like Mind StoneGolgari Cluestone that does something itself *or* can be cashed in (breaking the stone) for a temporary boost, or something that has a more passive effect like Meekstone or Horizon Stone where the stone is exuding power. These are more in line with a Spellbomb effect.
The red and black ones are way under powered compared to the other three. Additionally, the all one color cast/activation costs make them way too narrow for effective 7 mana abilities. I'd go 2U cast and 3UU activate, but then find some creative tweaks to Red and Black's abilities too.
Minor other quibble, the naming is all over the place - A titan and two gods (assuming it should be "Hades" and not "Haden") and two words unrelated to mythological beings is odd.
Thank you all for the comments. I made the corrections on the cards. White didn't have sacrifice and the green one didn't say anything about shuffling. And outside the game. Good catches.
Yes the names were originally intended to be based off of Mythology but the last 2 I didn't really like the names of the characters so went a little different route. Hades was intended to be changed. Not a typo. Haden Stone does sound a little better. If they were stone of then Hades would sound better. My opinion but there ya have it.
Someone mentioned about recurring them. That is kinda the point in a sense. Exile isn't a direction I want to go in. Because in the block I'm currently working on these objects are very sought after. The block is heavily multicolor with good fixers so while it is a strain to get the correct colors, as it should be in a multicolor deck, it is still very possible. But these are the relics that power the plane... Well they are believed to be but in the final set the plane's real power source is discovered and used.
Legendary Artifact
UUUUT, Sacrifice Cronus Stone: Target player takes an extra turn after this. Activate this ability only during your turn.
Prometheus Stone RRR
Legendary Artifact
RRRRt, Sacrifice Prometheus Stone: Deal 9 damage divided as you choose to any number of target creatures and/or Planeswalkers. Activate this ability only during your turn.
Haden Stone BBB
Legendary Artifact
BBBBt, Sacrifice Haden Stone: Destroy target creature then put a creature card from a graveyard onto the battlefield under your control. Activate this ability only during your turn.
Emergence Stone GGG
Legendary Artifact
GGGGt, Sacrifice Emergence Stone: Search your library, hand, or from outside the game for a Green creature card you own and put it onto the battlefield with a +1/+1 counter on it for each basic land you control.If you search your library in this way, shuffle it. Activate this ability only during your turn.
Lustration Stone WWW
Legendary Artifact
WWWWt, Sacrifice Lustration Stone: Choose a nonland permanent card type. Each player sacrifices all nonland cards except for cards of the chosen type. Activate this ability only during your turn.
Thoughts?
Blue - Probably needs to exile itself, artifacts are fairly easy to recur, especially in blue.
Green - Templating doesn't use "sideboard" its something more like "you own from outside the game". Also needs "If you search your library in this way, shuffle it."
White - Should say "permanent" instead of "card". If you choose Instant or Sorcery everyone just sacs everything, and also technically the way its worded you'd have to sacrifice Instants or Sorceries, which isn't a thing.
Other than that, I guess they just seem a bit weak. For 3 mana they don't have any immediate effect, and you're fairly restricted on how/when you can sac them, the effects are a little underwhelming. The red one seems about fine for 7 total mana, blue/black/white seem a bit overpriced for that effect, and the green one is maybe a bit too good given the +1/+1 counters. If it was for each basic land "type" instead of each land itself that seems reasonable.
Overall though, they don't seem like Power Stones to me. I always think of cards like Mind Stone Golgari Cluestone that does something itself *or* can be cashed in (breaking the stone) for a temporary boost, or something that has a more passive effect like Meekstone or Horizon Stone where the stone is exuding power. These are more in line with a Spellbomb effect.
Minor other quibble, the naming is all over the place - A titan and two gods (assuming it should be "Hades" and not "Haden") and two words unrelated to mythological beings is odd.
Yes the names were originally intended to be based off of Mythology but the last 2 I didn't really like the names of the characters so went a little different route. Hades was intended to be changed. Not a typo. Haden Stone does sound a little better. If they were stone of then Hades would sound better. My opinion but there ya have it.
Someone mentioned about recurring them. That is kinda the point in a sense. Exile isn't a direction I want to go in. Because in the block I'm currently working on these objects are very sought after. The block is heavily multicolor with good fixers so while it is a strain to get the correct colors, as it should be in a multicolor deck, it is still very possible. But these are the relics that power the plane... Well they are believed to be but in the final set the plane's real power source is discovered and used.