To start with. Unless you make this enchant only creatures you control it needs to be black(or red) because that first ability, more often than not, simply reads destroy enchanted creature.
In fact, neither the first nor the last ability are green.
I like the concept of that last ability but have you actually given it any thought? It simply won't function at all on any ability that requires tapping or a zone change. So I don't think there are many abilities it actually copies.
An ok effort but failed execution due to lack of rules knowledge and violation of color pie.
I'm struggling to find the actual rules question here. Let me address them as I can.
Panoptic Mirror - If its upkeep ability has triggered and you activate its exile ability in response. Then in response to that it's removed from the battlefield. Then you may still exile a card from your hand with mana value X and then it is a valid option to choose when the upkeep trigger resolves.
Isochron Scepter - If the scepter is destroyed in response to its activated ability it will still produce a copy.
Dino DNA - If Dino DNA is removed in response to its ability it will still produce a copy. Regardless of the state of the Dino DNA a card exiled with it will always be a card exiled by that specific Dino DNA. If the target of the ability is Pull from Eternity then no copy is made. As for why Dino DNA uses target and the others don't; the most reasonable answer I can give is they were created at very different times. While the Scepter has no want to say target as its expected to only have the one card imprinted. The Mirror, as one of the only multi-imprint cards of its time, could have simply followed suit so as to keep the same template for all imprint cards. Or it may be a product of its day. Notice how the Mirror doesn't exile its cards. It removes them from the game. They may have felt it awkward to directly target cards that weren't in the game. While with the exile zone being part of the game it's not strange for a card with multiple cards exiled by it to target if it wants to reference a specific one.
Do note, that you are drawing cards in this loop. And you have 5 mana available. So there is the chance, that you draw into an instant removal spell (if you run such in your deck) to kill Sheoldred before she kills you.
This is true and also complicates the situation a bit. If expecting to draw an out it must be noted that unless you also win with this out you only have half your lifetotal to draw this out. Every Vilis trigger results in two Sheoldred triggers but only one will resolve to perpetuate the loop leaving an additional unresolved trigger waiting to kill you even if you've dealt with Sheoldred.
Your gut is right, this won't work. Let's break it down.
Both cards on the battlefield, the stack is empty and you have 5+ black mana floating in your mana pool.
You declare you are activating Vilis's ability. You put the ability on the stack, choose a target. Then pay it's costs.
Vilis's ability is on the stack but you have lost life so you have a trigger waiting to go on the stack. This triggered ability goes on top of the activated ability so it will resolve first.
Once you've drawn this triggers Sheoldred. Which loops back to drawing. While the -1/-1 is still waiting at the bottom of the stack. You could activate it again but it will just place another loop on top of this one.
Despite the multiple problems that still exist I'm just going to focus on one thing. An effect can be worth more than 1 mana but less than 2 mana. That doesn't make it ok to put at 1 mana.
Though I've rarely vocalised it, I've occasionally questioned your grasp of the English language. I must do so once more. Do you know the meaning of the idium "F around and find out"? Cause these designs don't evoke that concept at all. The most common interpretation is take risks and suffer the consequences.
Moving on, your use of hybrid is once again antithetical to its purpose.
The nonsense of an opponent calling the coin flip complicates the spell for no gain.
There's no synergy between these effects. Look at the fuse cards. Each one is designed so that the fuse ability complements the two halfs. This is just stapled onto two completely different cards that wouldn't even want to be played in the same deck.
The effects in your coin flip are radically different in power level and impossible to plan around.
Random discard is more powerful than non random discard and mist be costed appropriately.
The reason split cards are costed more than a normal card is because of the value in adding both cards to your deck; doubly so for fuse that adds the value of casting the second card. Rather than adress this issue you've made a work around that only addresses one of the issues while ignoring the more important one.
Possibly the worst coherent card you've ever designed. It's not even worth a 0/10. It's like being asked 2+2 and responding "did you know taxonomically there's no such thing as trees."
This term "embedded trigger" doesn't exist in magic. Itzquinth has a reflexive trigger.
Roaming Throne doesn't work with reflexive or delayed triggers. The Throne looks for triggered abilities of creature permanents. Not triggered abilities of abilities.
603.2e Some effects refer to a triggered ability of an object. Such effects refer only to triggered abilities the object has, not any delayed triggered abilities (see rule 603.7) that may be created by abilities the object has.
603.12. A resolving spell or ability may allow or instruct a player to take an action and create a triggered ability that triggers “when [a player] [does or doesn’t]” take that action or “when [something happens] this way.” These reflexive triggered abilities follow the rules for delayed triggered abilities (see rule 603.7)
While your questioned was answered I feel compelled to add an answer to a question you didn't ask. Changing control of the equipment doesn't change what it's equipped to. So if your sword was equipped to a creature you control. It changing owners doesn't unequip it. The equipped creature still gets +2/+2 and protection. However, because the sword doesn't grant the sabotage ability but has it itself, should your still equipped creature deal combat damage to a player, even the current controller of the sword. The controller of the sword will gain the 3 life and return a creature to their hand.
Compared to March of Reckless Joy, as previously stated, there's no reason it couldn't exist and become an extension of utility to the color.
That is the essence of extending utilities to colors, boundaries and uniqueness, opposed to straightforwardness.
OMG, you're right. If you ignore the reasons against it there are no reasons not to do it. And if you do it, then it having been done opens the door to do it again and better. This will steadily allow every color to do everything. Shoring up their weaknesses until there are no strengths and the game loaes any reason for color other than a vaneer of flavor. Its almost like that was a reason it wasn't done in the first place but because we're ignoring those it just seems brilliant.
I'd like to point out how much closer this design is to Sign of the Cross, which no one would bat an eye at if printed.
I'm not going to ask anyone to click the link but I will explain. Only reap could link a thread where everyone condems a card as unprintable and claim no one would bat an eye if it was printed.
This is a level of cognitive dissonance that is down right impressive.
If the casting was legal then there would be no problem Boromir doesn't have any restriction on its sacrifice ability. So whether via a Hideaway mechanic or simply giving it flash via a Vedalken Orrery or similar card. Once Boromir is on the battlefield, unless some other card restricts the use of his ability he can sacrifice the same turn he enters play.
While interesting at first glance. Both just seem too busy to be made.
Unrestricted returning a permanent to hand from the graveyard already only costs 2. So whatever restriction is pushing it down to 1 has to be fairly benign or it becomes too limiting.
The value of a soft counter that gives you benefit if it fails to counter is a neat concept but there's a reason this hasn't been done in 30 years and it's not because no one thought of it. It applies pressure in a way that that is only feels bad.
In fact, neither the first nor the last ability are green.
I like the concept of that last ability but have you actually given it any thought? It simply won't function at all on any ability that requires tapping or a zone change. So I don't think there are many abilities it actually copies.
An ok effort but failed execution due to lack of rules knowledge and violation of color pie.
Panoptic Mirror - If its upkeep ability has triggered and you activate its exile ability in response. Then in response to that it's removed from the battlefield. Then you may still exile a card from your hand with mana value X and then it is a valid option to choose when the upkeep trigger resolves.
Isochron Scepter - If the scepter is destroyed in response to its activated ability it will still produce a copy.
Dino DNA - If Dino DNA is removed in response to its ability it will still produce a copy. Regardless of the state of the Dino DNA a card exiled with it will always be a card exiled by that specific Dino DNA. If the target of the ability is Pull from Eternity then no copy is made. As for why Dino DNA uses target and the others don't; the most reasonable answer I can give is they were created at very different times. While the Scepter has no want to say target as its expected to only have the one card imprinted. The Mirror, as one of the only multi-imprint cards of its time, could have simply followed suit so as to keep the same template for all imprint cards. Or it may be a product of its day. Notice how the Mirror doesn't exile its cards. It removes them from the game. They may have felt it awkward to directly target cards that weren't in the game. While with the exile zone being part of the game it's not strange for a card with multiple cards exiled by it to target if it wants to reference a specific one.
Both cards on the battlefield, the stack is empty and you have 5+ black mana floating in your mana pool.
You declare you are activating Vilis's ability. You put the ability on the stack, choose a target. Then pay it's costs.
Vilis's ability is on the stack but you have lost life so you have a trigger waiting to go on the stack. This triggered ability goes on top of the activated ability so it will resolve first.
Once you've drawn this triggers Sheoldred. Which loops back to drawing. While the -1/-1 is still waiting at the bottom of the stack. You could activate it again but it will just place another loop on top of this one.
A color interacting with card type is not precedent for interacting with different card type.
Your inability to break an effect isn't reason to break the color pie.
These are all color pie integrity mistakes that any competent designer should be able to recognize.
Moving on, your use of hybrid is once again antithetical to its purpose.
The nonsense of an opponent calling the coin flip complicates the spell for no gain.
There's no synergy between these effects. Look at the fuse cards. Each one is designed so that the fuse ability complements the two halfs. This is just stapled onto two completely different cards that wouldn't even want to be played in the same deck.
The effects in your coin flip are radically different in power level and impossible to plan around.
Random discard is more powerful than non random discard and mist be costed appropriately.
The reason split cards are costed more than a normal card is because of the value in adding both cards to your deck; doubly so for fuse that adds the value of casting the second card. Rather than adress this issue you've made a work around that only addresses one of the issues while ignoring the more important one.
Possibly the worst coherent card you've ever designed. It's not even worth a 0/10. It's like being asked 2+2 and responding "did you know taxonomically there's no such thing as trees."
Roaming Throne doesn't work with reflexive or delayed triggers. The Throne looks for triggered abilities of creature permanents. Not triggered abilities of abilities.
603.2e Some effects refer to a triggered ability of an object. Such effects refer only to triggered abilities the object has, not any delayed triggered abilities (see rule 603.7) that may be created by abilities the object has.
603.12. A resolving spell or ability may allow or instruct a player to take an action and create a triggered ability that triggers “when [a player] [does or doesn’t]” take that action or “when [something happens] this way.” These reflexive triggered abilities follow the rules for delayed triggered abilities (see rule 603.7)
Without a card I can't get more detailed but if a card says "reveal" it usually means "let everyone see".
This is a level of cognitive dissonance that is down right impressive.
Unrestricted returning a permanent to hand from the graveyard already only costs 2. So whatever restriction is pushing it down to 1 has to be fairly benign or it becomes too limiting.
The value of a soft counter that gives you benefit if it fails to counter is a neat concept but there's a reason this hasn't been done in 30 years and it's not because no one thought of it. It applies pressure in a way that that is only feels bad.