Commander
Deck list
View this Rionya, Fire Dancer deck list in Archidekt!
About Rionya
Rionya's ability is very intriguing forcing you to balance with creatures and cheap cantrip instants and sorceries. In red.
Rionya's ability is not straight forward and I'd recommend the deck for players with some experience and understanding of the stack since your commander is crucial for the deck to win games. You want to protect you commander at all times and I've noticed it is best to bait your opponents removals as often as possible with constant pressure from creatures.
As you know, red is not the strongest color for cantrip-decks due to the lack of permanent based card draw but Rionya is not interested in cantrip permanents but in cantrip instants and sorceries. I've enjoyed a lot with my Rionya deck and it has evolved a bit from the first 40€ budget to its current form.
Rionya, Fire Dancer in EDHREC
In EDHREC Rionya, Fire Dancer has under a thousand decks, 929. Rionya allows very different kinds of themes since the ability to copy creatures is only limiting factor. I'd say the most powerful build with Rionya is multiple combats theme as you get infinite loop easily.
Possible themes for Rionya
As said, Rionya's ability to create multiple token copies of a creature you control means the deck building is extremely versatile as your creatures define the wincon of your deck. This specific deck is between value and burn theme.
Value theme
Value theme was my first idea for the deck and it is still visible from cards like Scyscanner, Strike it rich, Solemn Simulacrum, Tavern Scoundrel, Birgi, God of Storytelling and Humble defector. I really liked the idea of a mono red value deck outvaluing the Volo, Guide to Monsters simic decks or Prosper, Tome-Bound decks.
Burn theme
More than often someone plays Propaganda or Ghostly Prison and in these times you are happy from all the burn damage you can inflict with strong ETBs and attack triggers. For this theme Rionya does really shine with the ability to end games in single turn with 4 copy token. The ultimate wincons for this are Tectonic Giant, Terror of the Peaks, Fanatic of Mogis and Scourge of Valkas. Terror of the Peaks and Scourge of Valkas are the strongest burn cards able to burn 80 dmg to any target with 4 copy tokens.
Big part of the deck is focusing on shutting down opponents creatures with multiple ping triggers from creatures like Goblin Chainwhirler and Scalding Salamander.
Token theme
Goblins are possibly the strongest archetype in mon red builds and I feel Rionya could pull it off, but definitely not as strong as Krenko, Mob Boss! With multiple "create x goblins" ETB triggers one could easily shift the deck in a token theme.
Steal theme
As Rionya's ability needs instant and sorcery casts to work one could also use the steal theme with steal spells like Act of Treason. Using this strategy your removals and most the creatures are steal spells and you copy you opponents creatures. Using this strategy is of course heavily dependent on your opponents creatures and will most likely cause you to turn to be the archenemy so be prepared for it.
Combo theme
Rionya, Fire Dancer combos to infinite combat phases with Combat Celebrant and Godo, Bandit Warlord. Mono red combos include multiple other broken cards eg. Kiki-Jiki, Mirror Breaker to achieve the same effect. This specific build does not have any (at least I'm aware of) infinite combos to win the game. Later on I might post cEDH version ohf Rionya, Fire Dancer if people are more interested in cEDH.
Strategy
Early game and mulligans
This build is low on mana producing permantents. With only 32 lands and 8 mana artifacts (I counted Ruby Medallion here) you need to carefully evaluate your starting hand. Minimum of 2 mountains and preferably something to cast latest on T2 is crucial to not to get killed by a Aggro Voltron deck. If you stay on curve until T3 your odds of survival are increased a lot. The deck has multiple strong wincons with burn effects so you don't want one in the starting hand! You will get one before casting your commander.
Best plays in Early game: Goblin Chainwhirler to shut down every manadork in green and Harmonic Prodigy to increase the synergies from Rionya.
Mid game
T4 to T6 are mid game where you disrupt your opponents games and bait the removals of your opponents. You need to "eat" a removal or two before casting Rionya, since the high mana cost is a challenge in mono red without rituals.
Great removal eaters: Vengeful Ancestor, Harmonic Prodigy, Solemn Simulacrum (sounds weird, but copying this bad boy 2-3 times a turn does give massive value), Terror of the Peaks, Coercive Recruiter and Tectonic Giant to name a few.
Late game
T6+ are the late game and you should have some ETB or attack trigger creatures on table. Most likely your hand is empty or have one card in hand. If your opponents have cards in hand and mana open it is better to not cast Rionya if possible. Never a bad idea to cast your flashback cards to fill your graveyard with loot spells like Faithless Looting and trying to get the Ox of Agonas there. Ox of Agonas is the strongest card draw effect in the deck but be careful for milling yourself or losing all wincons in the graveyard as the permanents are very hard to get out of the graveyard.
Winning the game
If you make it to the late game, and have cards in hand and able to cast Rionya, or even have it already on the table the chances are you are aiming to win the game during your next turn. Starting the turn with cantrips like Expedite, Crimson Wisps and continuing with rituals like Battle Hymn or Seething Song.
In our games 1 or 2 instants or sorceries is not enough to win the game but rather making Rionyas ability to be considered useful against other decks in terms of resources so if needed leave mana open and play the players and bluff you have interaction in hand even though you have only 3 Mountains in hand.
Who is the deck for
I've enjoyed alot playing with Rionya, and I dare to say it is my favorite deck! The combination of cards quite weak in other decks shine in Rionya due to massive copy effects. Especially the restrictions in the card pool has been refreshing as the amount of "same" cards in other decks is close to zero (with exceptions like Jeska's Will and Nykhtos, Shrine to Nyx).
Also the usability of graveyard is very interesting with spells like Shenanigans and Strike it Rich bringing huge value and being better than Shattering Spree or other format staples.
I'd say the Power level is max 7 due to the low amount of fast mana and Rionya having high mana value.