Book of Inferno Slot Overview
Book of Inferno from Quickspin is a 5x3 slot with 10 fixed paylines, set in a demonic underworld full of lava, beasts and jagged rock. The key twist is the Marked Symbol system, which can show up in the base game as well as free spins. I like that straight away, chat, because it gives the session more to do than waiting only for scatters.
Volatility is high, RTP tops out at 96.15%, and the max win is 5,846x the bet. Stakes run from 0.10 to 100, and it plays on mobile too. If I'm honest with viewers, the theme work and sound do a lot of the lifting here, because mechanically it is still built on a very familiar Book setup.
Book of Inferno Slot Features
Marked Symbols are the big talking point. A random symbol can become marked in the base game or bonus, and if enough of them land to make a win, they expand to cover the full reel. Once expanded, they pay anywhere and on all paylines, so they do not need to sit next to each other. That gives the base game a bit more life than the usual dead-spin grind.
Books also interact with that feature. When a Book lands at the same time as a Marked symbol, the marked icon upgrades to the next highest-paying symbol, which can create more marked symbols and more reel expansions. If the marked icon is already the top symbol, the lowest-paying symbol gets turned into the highest one.
3, 4 or 5 Book symbols trigger 10, 15 or 20 free spins, plus instant wins of 2x, 20x or 200x bet. At the start of the feature, the book picks one symbol to be marked for the whole round. That chosen symbol becomes the special expanding one, and the Marked Symbol feature can still trigger during free spins as well.
Retriggers are in place too. Land 3, 4 or 5 Books while the bonus is active, and you get the same number of extra spins again. In eligible markets there is also a Bonus Buy for 125x bet, which guarantees 3 or more scatters on the next spin and raises RTP to 96.65%. That version is not for UK players, so for stream value I would judge it on the natural bonus pace.
Bonus Buy Options
The free spins round can be instantly triggered from the base game by buying it for 125x current bet.
Feature Cost: x125 Bet
Random symbols can become Marked in the base game and free spins. If enough land to create a win, they expand to cover entire reels and pay anywhere on all paylines, without needing adjacency.
3, 4 or 5 Book symbols award 10, 15 or 20 free spins and pay 2x, 20x or 200x bet. A random symbol is chosen at the start to be the Marked symbol for the whole round, and 3 or more Books can re-trigger the same number of spins.
Where available, the free spins feature can be bought for 125x bet and guarantees 3 or more Book scatters on the following spin.
Feature Cost: 125xRTP: 96.65%
When a Book lands at the same time as a Marked symbol, the Marked symbol is upgraded to the next highest-paying symbol. If the Marked symbol is already the top one, the lowest-paying symbol turns into the highest-paying symbol.
Book of Inferno Slot Information
10 pay symbols sit on the reels. Low pays are 9 through A, and five of a kind on a line pay from 8x to 12x bet. The premium symbols are Commander of Hell, Lady of Hell, Lord of Hell, and Anna the Demon Huntress, with five of a kind worth from 75x up to 500x bet. Anna is the top one.
Book of Inferno is the wild and the scatter. It substitutes for regular pay symbols and also pays on its own, up to 500x for five Books. That part is standard for the genre, but the visual treatment of the book gets mentioned a lot in the source reviews, and I get why, it looks properly detailed on screen.
Symbol Payouts
