Book of Inferno

Book of Inferno from Quickspin is a video slot with a classic layout of 5 reels and 3 rows, as well as 10 fixed paylines. Thematically, it is set in an infernal atmosphere with flames, demons, and Anna the Demon Huntress as the main character, where visual effects and dark surroundings set the mood. The game features a distinctive "Book" symbol, which acts as both a wild and a scatter, thus able to replace other symbols and trigger Free Spins.

One of the central features is the Marked Symbol mechanic, where a random symbol is selected, and when there are enough of them for a win, they expand to cover the entire reel and pay "anywhere" without a requirement for a sequence from left to right. Any Book symbol that lands alongside the Marked symbol upgrades it — meaning that the Marked symbol shifts to a higher symbol level, and if it reaches above the highest, the lowest symbol is transformed into the highest.

Free Spins are activated by 3, 4, or 5 Book scatters, awarding 10, 15, or 25 free spins, respectively. Along with the Free Spins trigger, a win multiplier of 2×, 20×, or 200× the bet follows, depending on the number of scatters. During Free Spins, a symbol is randomly chosen as Marked, and the Marked Symbol feature continues – with the possibility of upgrades throughout the bonus round.

There is also a Bonus Buy feature, where players can pay 125× their bet to buy directly into Free Spins, guaranteeing at least 3 Book scatters on the next spin and activating the bonus round without delay. The feature is not available in all jurisdictions.

Overall, Book of Inferno combines traditional "Book slot" elements with advanced mechanics such as expanding and upgrading symbols, making the game more dynamic than many others in the same genre.

You can try it for free in demo mode or play it for real money.