It was late 2018 during the first Twitch Rivals tournament for Magic: The Gathering Arena and Caleb Durward was one win away from $10,000. Only one player stood in his way, Hearthstone veteran Morteza "Rage" Rohaninejad.

"He had been known for playing really complicated decks in Hearthstone, but he had only been playing Magic for a month," Durward said recently. "So it was cool to meet him in the finals."

Durward had one big advantage. He had been playing Magic: The Gathering for almost 20 years since he first built a deck when he was 10. Rohaninejad had been playing for much less time. After an intensely close game, Durward sealed the first-place finish.

"I had played the limited format of Magic for about a month or so, I played standard for about a week and just tested a bunch of decks," Rohaninejad said. "My Hearthstone skills definitely helped."

Since its launch in 2014, Hearthstone has continued to dominate the card game market. The combination of it being one of the first major digital card games to launch and the tie-in with World of Warcraft has drawn in over 100 million registered players and built a strong competitive community and ecosystem of tournaments and teams. But competition, mainly from Magic: The Gathering Arena, which officially launched last year after a long beta period, has finally started to rise up.

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Other card games have flooded the market since Hearthstone's initial success. Bethesda released and then ceased development on Elder Scrolls Legends, Valve had an incredibly messy launch for Artifact (and claims to be completely overhauling it), and The Witcher 3 developers have maintained a healthy player base for Gwent. Riot Games just launched Legends of Runeterra in January, and Capcom released the real-time card battler Teppen, which used notable franchises like Resident Evil and Mega Man, last year.

"Card games are an easy way to make an all-star combo game; the genre makes that simple," Capcom and Teppen executive producer Ryozo Tsujimoto said ahead of the first Teppen World Championship in December of 2019. "It's also easy to make it accessible to a lot of different types of players."

All of these card games have also spawned vibrant and passionate competitive communities.

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It's no doubt that other studios and publishers followed in Activision-Blizzard's footsteps after seeing Hearthstone's success, but no one has been able to come close to it and grab a bigger chunk of the $2 billion card game market forecast for 2020. Until now. Wizards of the Coast's Magic: The Gathering Arena might be the game that finally challenges Hearthstone for the card battling throne. While Hearthstone's monthly hours watched on Twitch dropped over the course of 2018 and into 2019 to below 20 million, Arena's rose to 10 million.

No other card battler got close.

Hearthstone's first-to-market advantage may be drying up now that it has a comparable competitor in Arena. Several of the competitive players, streamers, and casters ESPN spoke to this story said they play both, but can only focus on one at a competitive level.

"It's really hard to master and stay current even though there are a lot of similar mechanics and such," Durward said. "There are Hearthstone players that have gotten into Arena, but they still focus on Hearthstone."

"Every single card game out there is loosely based on Magic in some way," Team Liquid Hearthstone streamer and player Ryan Root said. "People have health totals, play units and cast spells. It's hard to put together without these basic premises."

While Hearthstone's tie-ins with the lore of the Warcraft series helped entice new players and attract card game veterans when it first launched, Magic: The Gathering has a much deeper legacy than any other digital card game -- something that resonates with players like Durward. Wizards of the Coast launched the physical cards in 1993 and has been releasing new cards ever since. Magic Online and Arena are just extensions of the classic card game, while most other games like Teppen or Hearthstone were developed more recently.

"Plenty of people, including competitors, that play Arena now came from playing the physical versions of Pokemon, Yu-Gi-Oh and Magic," said Eilidh "AliasV" Lonie, an Arena streamer and caster who started playing Gwent but made the jump to Arena last year.

Many of those players went to Hearthstone at first because "it was the first online card game that got it right," she added. Well known competitive Hearthstone player and former caster Brian Kibler started competing in Magic tournaments when he was 15.

Now that the field is crowded and Hearthstone might be losing the edge it had, it's up to the game developers at Activision-Blizzard, Wizards of the Coast and other studios with card games to show current players why their title is the best. A card game needs ongoing fresh content, standard accessibility features, widespread availability and a fair monetization system (Artifact's player base was killed by its "pay for everything you do" system) if it wants success.

Right now, every studio's approach is a little different.

Activision-Blizzard puts its money on creating moments in the game. The developer recently closed out a yearlong in-game storyline, the Year of the Dragon, that ended with a special event known as Galakrond's Awakening. That event brought 32 new cards to the game in a new narrative adventure, and those story-focused expansions are one of the ways Hearthstone's development team has kept players invested in a near 6-year-old game.

"Whenever you log into Hearthstone, we want the meta to keep you on your toes," Hearthstone lead for card design Dean Ayala said.

Arena, on the other hand, has been adding different formats and cards during regular intervals since the game launched in beta.

"As Arena ages, I think it's going to age really well," Durward said. "As more and more cards come to Arena those older formats are going to develop and complexify. It's a really fun game to stream because it's like streaming ten different games. Arena isn't quite there but it's getting better and better."

The debate about how often card games should be updated with new content is an ongoing one, and the answer is different for casual players, competitors, and streamers. Root, for example, said the Year of the Dragon had too many updates: Too many new cards, he said, can be a problem for more casual players.

"Obviously, the more you play, the more you want updates; the less you play, the harder it is to keep up," Root, who streams eight hours a day, said. "For game-makers, it is an ongoing battle to keep as many players engaged in the game. I think this time around, the Hearthstone team overdid it on content."

While Hearthstone and Arena's update schedules differ, they both receive new content regularly enough to bring in new players -- both those who are familiar with card games and those who are completely new to the genre -- and retain those fresh faces. While Arena has the 27-year legacy of Magic: The Gathering, Hearthstone has had more iterations and accessibility features to keep people playing. Blizzard's title also has the advantage of being available on phones, although Hasbro announced Arena will be coming to mobile later this year.

One thing that multiple casters, players and streamers told ESPN is that competition in the card game market is a good thing. Hearthstone has been king of the mountain for a big part of the genre's lifespan, and while Activision-Blizzard has continued to introduce new content, competition could improve the experience with new features, formats and accessibility options for players who enjoy either game.

"Healthy competition is always a good thing," AliasV said. "I do think Wizards of the Coast do want Arena to compete with Hearthstone, but Hearthstone is still king of the cards. I'm hopeful that they'll continue to grow, learn and listen to community feedback."