It's currently on season 2. I started this game around two months ago by serendipity when checking some discord games.
Spark: Hero Tactics is a card battle game on a 3x4 grid where the objective is to destroy the other player's fortress. It's free and developed by the Discord team.
Here's a link to the game's FAQ page where it details the gist of the game Spark Hero Tactics FAQ.
What You're Getting Into:
There's not a lot of content out there that promotes the game and there's only a players active daily. Because of the limited pool of players, you're more likely to encounter bots that real people most of the time.
The leaderboard doesn't really reflect skill but tells me who has a lot of free time to play the game with bots (and occasionally people). I'm currently rank 5 on the global ladder because I still have a life outside. The community on Discord is chill and welcoming so you'll settle right in if card fights like these are your thing.
Is it pay to win? no, you can grind through as free to play and still get a good run much like how I ranked up on the top. Once you hit a rank (Ascendant) where your badge looks like Hive's logo, you're already at the top 50s of the game.
Is it challenging? yes, there's a lot of difference between how bots play and real people using the same decks so being at the top isn't just for show. The game is really generous at giving people bonus packs from quests so anyone that has played the game for just about a week can get a decent deck.
The real fun begins when you are ranked as an Ascendant because that's where the creative and competitive decks are encountered.
You can play the game through Discord and starting an activity to see the game on the lists.
A link to Spark:Hero Tactics Discord
Not affiliated with the game. I just play it for free.
Thanks for your time.