This guide covers the basics until first game reset.

When you start this game, all you can do is purchase an Agriel. But you'll need to know some things.

- Agriel, as every bottom character in every faction, are resource producers.
- Agriel is the gem producer, and gems are the resource produced by the Demon Faction.
- Ghoul is the soul producer, and souls are the resource produced by the Undead faction.
- Leviathan is the Raw Mana producer, and Raw Mana are the resource produced by the Drowners Faction.
- Every other unit in the game excepting the bottom character in each faction only produce the unit directly below them
- For example, a Dantalion will produce Agriels.

To start the game and it's fearsome upgrade spiral, you should use your starter gems and produce a Agriel, which will be slowly start producing gems.

When you get enough Agriels, you'll be offered an update. And here is the trickiest part of the game.

On the left side of the screen, you'll see the Faction's tabs. To the right of that you'll see a list of resources and units of that faction. To buy a creature, click on it and select Create one
The next area to the right shows information about the current unit or resource selected and the final area opens up when you are ready for the first reset, with several options.

In most idle games you upgrade as soon as the upgrade appears. If you do that in Underworld idle you risk making the game more difficult because UPGRADES CONSUME UNITS.
Each upgrade doubles the power of the remaining units so, as a general rule, wait till you have double the units needed to do an upgrade. Because if you upgrade as soon as the unit shows the asterisk (*) that indicates it's ready for upgrade, you'll find yourself with almost no units of that type.
Later on, when you start getting how this works, you'll notice the difference in each upgrade due to the speed at which each unit is being produce in relation to the required units for the upgrade. And if the speed is high enough, you can forget about doubles, upgrade and know that you'll get back on track almost immediately.

Gems also get something that resembles an upgrade popping out every now and then. Instead of gems getting more powerful, what you get is the option of buying Sphere of Fire and Fire Skull. It's not like you can select whichever you want, each has a price in Gems. Sphere of Fire can be give to any Demon that has been upgraded at least once. Fire Skull can be given to Undead that have at least one upgrade. This gems offer a 50% productivity increase, and you can give more than one to a single unit, though they get diminishing returns.

Souls have a similar mechanism. They offer Rotten Doll and Altar of the Soul. Rotten Doll gives Waste, and each time you buy one, the next one gives a little more Waste, and they also increases by 1 the amount of waste received by exchanging souls in the graveyard. Altar of souls adds decimals to the soul cost, letting it drop lower and lower for units that have a higher unit above them.

The energy starts at zero, and remains that way till you get enough gems to unlock the first button. Each button offers a different option, and the energy they require will get replenished slowly over time. You'll also get energy every time you unlock a new button. The buttons are all either percentage based or scale up as you grow in power, so they are always useful.

The fifth button has a mechanic for unlocking the Warlock faction, but you won't get access to that in the first game reset, and you'll probably need several resets till it gets good enough to get all the necessary resources, so don't worry about it for now.

Each button you purchase offers a 0.1 increase to the base 0.25 energy per second, so by the fifth button you'll be generating 0.3 energy per second. Later mechanics will improve this but you'll have no access to that at the beginning.

you'll start the game with Demon units that require Gems and Souls, and soon realize that higher units not only produce lower units, they also require lower units to buy. It's not as big of a problema as upgrades, as you are producing more higher units that will produce more of the same lower units they require. You'll also see that as you get more higher units, the soul cost of the lower unit is decreased. This helps in getting cheaply more lower units to buy even more higher units. This is a mechanic that you'll love later in the game.

It should be noted that as you get higher and higher units of a faction, it makes no sense to buy the lowest units anymore, as the amount you'll get is not significative to alter the game. So you'll start to control de amount of lower units by getting more highest units that cascade production down.

After you pass the threshold of the first undead, which produces souls, you'll notice that it requires Gems and Souls, but also Raw Mana. You have 150 Raw Mana, so you'll be able to get some ghouls to produce more souls.

It gets trickier for the Drowners faction, as they require Gems and Souls, but also Waste. And Waste is not a product of your units. Instead, you'll need to go to the Waste tab, that'll direct you to the Junkyard. Here you'll find some options for getting waste by sacrificing Gems, Souls or Raw Mana, but only after you pass each required amount. You'll also be able to get some waste by special upgrades of souls, but not in a continuous way.

Lastly, waste can also be found when you reset the game by using one of the demon's boilers.

In the junkyard tab you'll also find the daily junkyard search and the monetizing options of the game. The daily option it's not really daily. Each time you use it, it'll take 24 hours from that moment to activate again, so that option is always shifting in time. The good news is that it also counts the time you are not playing the game.

That takes us to the most particular aspect of this idle game. The offline time counts only for three things.
1. the daily junkyard timer
2. energy recharge
3. waste retrieval

I find it funny that the game does not give us any gems, souls or raw magic, but the most limiting resources: The energy that's so hard to wait for and the waste that's difficult to get.

The junkyard also lets us collect three scarce resources, a part of the monetization of the game. Every daily search can give us some Tokens, Battery or Gear. Tokens are a way of getting more Battery or Gear, and besides the ones in the daily search, you can buy more with money. Batteries are used to replenish Energy for the buttons, and Gears are a permanent upgrade for the unit that gets assigned one that remains between resets.

If you go into buying tokens, then you should know that there is another option to spend them: Artifacts. Artifacts are permanent upgrades. If you don't decide to support the game, then know artifacts are there but you won't be able to save for them in this first reset,

As one of the earlier unblocked permanent items, it's important to know where to put gears. In the early game, it's best to assign gears to the drowners faction, as they are the ones that don't get non permanent bonuses early on.

If you make a mistake, don't worry, you get gear resets so that you can assign them again.

When you get at least 35 hell ashes you'll unlock a new feature called runes, that will appear as a new option in the Demon's faction.

Runes start slow, and you need to manually start the creation of each one, an change it when deciding to build another. When each rune reaches 100% completion rate it'll unlock a new bonus.
- Fehu rune is the lowest, 100% gives 10x gem production, the only free rune.
- second is the Jera Rune: 100% gives 2x productivity for all demons. Requires 5% Fehu runes to create
- third is the Hagalaz Rune: 100% gives 1.5 for all energy crystals. Requires 5% Jera Runes to Create.
- fourth is the Runic Prism, which I frankly yet don't know if it has a 100% completion bonus, though the community has hinted that it does have one.Requires 5% Hagalaz Runes to create, and takes a long time.

As described above, higher runes can be created by consuming 5% of the previous rune. This means that you'll need to create again the missing lower runes but now you have some bonuses to the creation speed of the lower rune. It then becomes a balancing act between constructing lower runes to get higher runes to get more speed to create more lower runes.

This continues two steps up, Fehu to Jera to Hagalaz till, at the third step you'll find a different kind of rune. It takes a lot of tine to build each Runic Prism, but the payout is incredible. Previously you got bonuses to the speed of the rune below, The Runic Prism gives speed bonuses to all the three runes below it. And it does so to incredible speeds. If you level it enough you'll start seeing new information besides the create rune button, and it will read (several runes will be created) unlocking thus a one push automatic creation.

It should be noted that this is not a permanent system until you blow your boiler room and get the Permanent Runes contract. If you don't have that, resets will make you start from 0 again. Get this contract, it's only 50 prestige and makes this system permanent.

Lastly, the Runic Prism takes so much time to create that it has an option of investing 10k energy to fasten the creation. For me that's a little overpriced, as wait is what we are used to do in this game, but I must admit that the result is great as the option doesn't speed it a little, it fills the bar completely in a few seconds while it consumes the donated energy. And this is a rune that takes a lot of seconds to create, so many seconds that they become hours, and later on they become days.

While rune creation doesn't work offline, some of the runes have bonuses that are applied to the units and those do work offline.

When you go to the Junkyard (the Waste tab) you'll see that besides waste, each Gem sacrifice gives Hell Ashes. When you reach 75 Hell Ashes you'll be able to go to the Demon Faction, and then go to the new option that appears, the Boiler Room. You'll also notice that there's another new tab, called Contracts. Demon Contracts require prestige, and are permanent upgrades for the game.

To get prestige, you blow up the boiler, and it will say exactly what you'll get. In the Demon's case, you'll get waste and prestige. The more Hell Ash you have the better the rewards. When you blow up the boiler, the game starts again, but this time the Boiler Room will be open with two boiler options and you'll be able to use prestige to get some contracts.

Each contract offers a different game modification, and even different number of levels you can get. So, get your contracts and then purchase your first Agriel again.

I hope this helps you understand the basics. There's much more to discover.