Serpent King: Slot Overview

The lion might be the classic “king of the jungle,” but in this case the crown goes to something far more unsettling. A menacing reptilian creature sits at the top of the food chain in Red Tiger’s online slot Serpent King. If it feels familiar, that’s because the game connects to earlier RT titles, Primate King and Primate King Megaways. As with those releases, upgrading the wild symbol and eventually opening up a sixth reel are core parts of the experience, supported by several additional mechanics.

Serpent King once again drops players into a thick jungle setting, where you can test your luck while trying not to become a snack for the sharp-ended resident. The “serpent” isn’t a typical snake; it’s more of a fantasy monster with glowing blue eyes, clawed limbs, and a frilled mane. It’s the last thing you’d want to meet while wandering the torch-lit ruins shown in the background, but it can also appear as a full reel wild multiplier symbol—so the more often it shows up, the better.

Just like before, the layout technically runs on 6 reels, although the rightmost reel is locked at the start. After all 3 Serpent Wild upgrades are completed, the full 6 reels become active. Each reel displays 4 rows, and the game uses 30 paylines paying from the left. Players pick a stake from 10 c to $/€6 and then spin under a medium-high volatile math model. The default RTP is slightly higher than in Primate King, coming in at 95.7%.

The scaly club, diamond, heart, and spade icons make up the low-value symbols, paying 0.6 to 1.5 times the bet for a 5 OAK line win. Because premium symbols can also appear on the sixth reel once it’s unlocked, the necklace, potion bottle, skull, and treasure chest can return 6 to 30 times the bet for a 6 OAK combination.

Serpent King: Slot Features

Serpent King carries over parts of Primate King’s toolkit while tweaking and expanding the set, resulting in Gold Coins, a Progress Bar, the Serpent Wild, a Multiplier Stone, and Serpent Respins.

Gold Coins & Progress Bar

As long as there are Serpent Wild upgrades to be unlocked, Gold Coins can appear on the bottom-right corner of any symbol on the grid. When Gold Coins land on the same spin as a Serpent Wild, they are collected and added to the Serpent Wild progress bar. Gathering 30 Gold Coins unlocks Upgrade 1, 60 collected Gold Coins unlock Upgrade 2, and 90 collected Gold Coins unlock Upgrade 3. Until all 3 Serpent Wild upgrades are complete, the Serpent Wild progress bar sits beside the 5 reels to show how far you’ve progressed. Once all 3 Serpent WIld upgrades are done, the Serpent Wild progress bar converts to a sixth reel. Card suit symbols cannot land on this reel.

Serpent Wild

The wild replaces all paying symbols and is upgraded as Gold Coins are collected:

• Upgrade 1 – changes the Serpent Wild into a 1×4 sized symbol.
• Upgrade 2 – applies a random multiplier to the Serpent Wild. Possible values are x2, x3, and x5.
• Upgrade 3 – upgrades the Serpent Wild into a Locked Wild. It remains on the reels until it takes part in at least 1 win, followed by a non-winning spin. With each consecutive win it contributes to, the win multiplier rises by 1. The Serpent Wild is unlocked after the first non-winning spin that follows at least 1 winning spin. While the Serpent WIld is locked, if it is on the fifth reel and has not been in a win, it may randomly move to 1 of the first 4 reels.

Multiplier Stone

If a Serpent Wild with a multiplier is visible but no win lands, the wild can store its multiplier inside the Multiplier Stone next to the reels. That saved multiplier is then transferred back onto the Serpent Wild the next time it appears, adding the stored amount to its multiplier.

Serpent Respins

Whenever the Serpent Wild lands and no win is formed, it may highlight a single symbol type on the grid. Every instance of that symbol is locked on the reels, and a respin begins. Respins keep going as long as additional symbols of the selected type continue to land. Only winning lines made up of the chosen symbol type are paid when the feature ends.

Serpent King: Slot Verdict

When Serpent King first appeared, it was easy to assume it would be a straight clone of Primate King. Mechanically, the two do share a lot, but there are also enough changes to separate them. The headline remains the same: upgrade the wild by collecting Gold Coins, with the same three-step path as before—the wild becomes 1×4, random multipliers can be added, and it gains a sticky-style behaviour. Each upgrade is beneficial, and they’re solid incentives for players prepared to stick with the progression system until it’s fully completed. Of course, some players may dislike the idea of having to “level up” a slot at all, which is fair. Red Tiger clearly enjoys this format, though it won’t suit everyone.

Where Serpent King stands apart is the Multiplier Stone, which can bank and then reapply multiplier values, plus the Smash feature being removed. The progress bar once again turns into a sixth reel that excludes low-pay symbols, but this time there’s also a respin feature—something Primate King didn’t offer. On top of that, Serpent King has much stronger win potential, reaching 12,825x the bet, which is roughly 3 times higher than PK and notable given there’s no bonus round or free spins feature.

These feature tweaks, along with the adjusted stats, do create more separation between Serpent King and Primate King. So, if you enjoy slots that improve the longer you play (as features upgrade, up to a limit) and you don’t mind a reptile-led theme, Serpent King is worth a look.