Book of Inferno Demo: Anna Hunts Demons on Ten Lines

A strip of ten icons over the reels, and one of them lit

Across the top of the board runs a row of small icons, the paytable in order: 9, 10, J, Q, K and A, then the Commander, the Lady and the Lord of Hell, and Anna at the right-hand end. At €1.00 a line of five Annas pays €500.00, five Lords €160.00, five Aces €12.00 and five Nines €8.00.

Whichever icon glows is the Marked symbol. According to the rules screens, a symbol can become Marked at random on any base spin, a point Quickspin's web page leaves open, and it happened on 23 of our 500 paid spins, about one in 22. Landing on enough reels to pay, it fills each of those reels and pays anywhere on a line, with no need to start on reel 1.

An expanded reel covers all three rows, so an expansion pays on all 10 lines at once. Jacks on three reels paid €5.00 on our last spin, ten times the €0.50 line price, and a Marked Queen on four reels paid €30.00 on spin 214. Demons need only two reels: a Marked Lady of Hell on two was worth €5.00.

Each Book pushes the mark one rung to the right

Books substitute for every symbol, pay as a symbol (€1.00 for two up to €500.00 for five at €1.00), and upgrade a Marked symbol they land with by one step, "potentially creating more Marked symbols and expansions", in the help screen's words. Past Anna, the lowest symbol is converted into the highest.

Our best base spin shows what that phrase means. On spin 144 the Jack was Marked at random and two Books lifted the mark two rungs to the King. In the server's expanded grid Kings then covered all five reels, though reel 2 held only a Jack and reel 5 only a Queen: each rung the Books passed stayed Marked and expanded as the top one. Five reels of Kings on 10 lines paid €120.00, 120.5x with a small line win.

Upgrades were far rarer than marks: a Book met a Marked symbol on 4 of the 23 marked base spins (spins 144, 280, 387 and 469).

10, 15 or 25 free spins with a one-spin upgrade

Books in threes, fours or fives start 10, 15 or 25 free spins and pay 2x, 20x or 200x the bet, and a retrigger adds the same counts. As the round opens, a random symbol takes the mark and keeps it to the end. No multiplier appears anywhere in the rules.

Our only natural bonus came on spin 127, one spin after the session low of €4,930.00. Three Books paid 7.5x with the line wins and the King was Marked. On free spin 2 one Book lifted it to the Ace, Aces and Kings covered all five reels and the spin paid 120x; free spin 4 added 5x, the other eight paid nothing, and the round finished at 132.5x, our best spin.

All along, the server kept the King as the round's Marked symbol, and the expansion on free spin 4 used Kings again. In this round, at least, an upgrade counted only for the spin its Book landed on.

A round from the badge costs 125x and comes with 3 or more Books "with the same frequency as when triggering it by chance". Quickspin prints no buy RTP (SlotCatalog and Bigwinboard list 96.65%), and the buy may be missing in some markets.

The menu says Wilds where the rules say Books. Our one bought round, played at €1.00 apart from the log, landed three Books on the bought spin for €9.50, and the Lady of Hell was drawn as the Marked symbol.

She never landed on enough reels to expand. On the tenth and last spin a Book on reel 3 passed the upgrade to a lone Lord of Hell on reel 1, one Lord short of a win.

Small line wins, the bought spin included, took the round to €13.50, or 13.5x against the 125x price. One round proves nothing about the buy; the clip shows all of it.

Half of our €537.00 came from marks in the base game

Five hundred euros in, €537.00 out: 500 paid spins at €1.00 returned 107.4%. Wins landed on 143 spins, whose median was 0.5x, and the worst losing streak lasted 13 spins, short for volatility 5 of 5.

• 500paid demo spins at €1.00
• 28.6%of them paid something
• 132.5xbest spin, free spins round included
• 1free spins bonus triggered

Two jumps and a long slope make up the line: spin 127's bonus, spin 144's Kings, a peak of €5,207.00 on spin 220, then a drift down to €5,037.00.

Counted in the server log, the 13 base-game expansions paid 265x between them, 49% of everything returned, against 25% from the bonus. By Quickspin's sheet the base game supplies 64.69% of the RTP and free spins 31.45%, so a base-heavy session fits, if not by this margin. A 100x win comes 1 in 572 spins on the sheet, and a sample of 500 says little about that figure; we hit it twice.

Anna's second Book game, set beside Duat, Yuletide and the Ark

Anna's first Book game was Book of Duat (November 2021), and it plays differently: 3 or more Wilds open a Pick and Click screen and 4 free spins with picks for expanding symbols and a multiplier, and three buys run from 150x to 1,600x. Its top win is 32,670.5x on the demo server, and free spins hold 39.59% of its RTP on the sheet.

Duat's rules and maths came back in a Christmas skin as Book of Yuletide (November 2023). Quickspin calls all three Book games and never a series; the expanding symbol is what they share.

Anna first appeared in Ark of Mystery (2018), a respin game on 20 lines without free spins, then in Dinosaur Rage (2021). Inferno is her cheapest game here, from €0.10 a spin against €0.20 for Duat.

Book of Inferno suits players who like the Book formula but want the base game to count: in our log the random marks out-earned the bonus, and the sheet gives the base game a bigger share than Duat's does. The ceiling is modest for volatility 5. For one big round with a far higher top, Duat fits better.

• Book of Yuletide review
• Book of Duat review
• Brawler's Brew review

Marks, Books and buys, settled one at a time

We checked every answer against the rules screens, Quickspin's sheet and game page, or our two logs.