Book of Aztec King Slot by Pragmatic Play

Mystery Symbols on Every Spin

Most "Book of" slots save the expanding symbol mechanic for free spins. Book of Aztec King runs it during base game too. Every spin, one random symbol gets tagged as the mystery symbol and expands vertically when it forms a winning combination. That means the Aztec King at 5,000 coins for five of a kind can fill entire reels before you even trigger the bonus round.

The grid is standard 5x3 with 10 paylines. Aztec King and Aztec Queen sit at the top of the paytable (5,000 and 2,000 coins for five), followed by a jaguar and toucan at 750 each. Five card royals (A through 10) fill the 100-150 coin range. The book acts as wild and scatter combined - three or more anywhere trigger 10 free spins, and five books pay 200x total bet on their own.

Free Spins: Double the Expanding Power

Trigger free spins and the game selects two expanding symbols instead of one. Both symbols expand to cover full reels whenever they appear in winning positions. The selection is random, so you might get the Aztec King and Queen both expanding, or a high symbol paired with a low one. That randomness is the feature's biggest variable.

Ten free spins per trigger, with retriggers awarding 10 more each time three books land. No cap on retriggers. Special reel sets are active during the feature, which typically means higher-value symbols appear more frequently than in base game. With two symbols expanding simultaneously, a lucky reel set can stack wins across multiple paylines in a single spin.

What It Doesn't Have

No buy feature. No ante bet. No jackpots. Book of Aztec King launched in March 2022, before Pragmatic Play started adding those extras to every "Book of" release. Newer entries like Book of Candy and Book of the Fallen offer feature buys at 100x and Super Spin ante bets at 10x - options this game simply doesn't include.

For some players, that's a drawback. For others, it keeps the game focused. You're playing for free spins through natural scatter landings only, which means the base game mystery symbol pulls more weight here than in versions where you can buy straight into the bonus.

Aztec King in the Book of Lineup

Compared to its siblings: Book of the Fallen has one expanding symbol, a buy option, and a 5,000x cap. Book of Candy adds jackpots and player choice of expanding symbol but stays at 5,000x. Book of Aztec King offers the highest max win of the three at 5,500x, the only base game mystery mechanic, and the only free spins round with two expanding symbols. It trades the modern convenience features for stronger core mechanics.

At 96.50% RTP and high volatility with a 4-year track record, the math is well-tested. The trade-off is clear: more powerful expanding mechanics, fewer ways to shortcut into them.