I am working on a lit-rpg novel where the universe is called Arcus, and it has three types of planes of existence: Imminus, Medius, and Summus. Each plane has its own characteristics, inhabitants, and environments.

The Imminus plane is the highest and most powerful plane. There are only nine of them, and they have a level cap of 99. They are also the capital and megalopolis realms of the Arcus universe. They are infinitely expanding and everlasting.

The Medius plane is the middle plane and one of the metropolitan planes of Arcus. They are subordinate planes of the Imminus realms, and each Imminus realm has nine Medius planes under it. They have a level cap of 69. Unlike their parent plane, they are not infinitely expanding but are infinite in size and everlasting.

The Summus plane is the lowest and weakest plane, with innumerable realms under each Medius realm that have a level cap of 39.The planes vary in size, ranging from the scale of a planet to that of a galaxy or a self-contained galaxy-sized realm. The Summus realms are also finite in terms of resources and lifespan. They will eventually deplete their energy and collapse into nothingness, unlike the other two planes, which are infinite and everlasting.

The problem is that I want to make the Summus plane relevant for higher realms in some way and my novel. I don’t want them to be just forgotten or unimportant realms where weaker inhabitants are born and migrate to higher realms after becoming powerful enough, like in cultivation novels. Because of the level cap, people need to migrate to higher-level realms to get more powerful. However, if a character is beyond the level cap and decides to migrate to a lower realm, then his or her level will be reduced to the level of the lower realm and they will become weaker.

So, how do I make them unique or valuable so that higher realms would need or want something from them?

  • $\begingroup$ You might get better traction if you don't mention how this is for a LitRPG novel. Don't mention the level system. Just mention the things the levels are an abstraction of. $\endgroup$
    – Daron
    Commented Sep 30, 2023 at 9:37
  • $\begingroup$ There are only three planes of existence, and nine of each of them? And these planes have level caps? This is very confusing. $\endgroup$
    – Joachim
    Commented Sep 30, 2023 at 9:54
  • $\begingroup$ Please note that the Latin word summus means "highest", and that **imminus is not a Latin word at all, although it does resemble the word imus, which means "lowest". Calling the lowest plane of existence Summus will surely result in a lot of confusion in the minds of your educated readers. $\endgroup$
    – AlexP
    Commented Sep 30, 2023 at 10:12
  • $\begingroup$ You are inverting the logical pyramid of progression in RPGs : You're restricting the amount of progression resources (XP, items...) for lower levels, while you should do it for the higher ones. Remember that unless people starts at different levels, you will always have more total people venturing in the lower levels than in the higher ones. When your lowest plane goes out of resources, it means no one will ever be able to join this universe anymore. This means you get a dying world, basically. This also kinda messes up your challenges vs rewards system so dear to RPGs. $\endgroup$ Commented Sep 30, 2023 at 10:54
  • $\begingroup$ @AlexP Thank you for bringing it to my attention. I was using chatgpt to help me come up with latin names as I suck at it. I guess I mixed it up then lol. $\endgroup$
    – user84527
    Commented Sep 30, 2023 at 11:16

5 Answers 5


Natural Resources

People keep coming back to the lower planes, because the lower planes are full of raw materials that everyone wants.

They have coal, oil, gems, ore, arable land, forests for lumber. Maybe some less mundane stuff like magical artifacts, dragons' teeth and rare herbs or potions. The lower planes are chock full of whatever you need to keep an industrial society chugging away.

The upper planes are empty because they exhausted their resources long ago. This is because they started with resources, ate them all up, and then continued to exist.

The lower planes, on the other hand, are transient planes. Every 1000 years the current lower planes are absorbed by the abyss and disappear. But the abyss then generates new lower planes, with new natural resources. No one knows this because people don't live that long.


The higher planes are everlasting only because of the lower planes

Lower planes spawn in at time to time and materials isekai up to higher planes. This allows them to sustain themselves and keep on growing.

This means that resources on the higher planes are finite, if the wrong things happen on lower planes. A rare herb that you need for a special pill might become non existent if the lower plane that produces it becomes ruled by a blood knight who burns all plants. As such, the politics between realms is important, as if they want to maintain their supply chains they need to ensure the right realms stay around and stay stable.



There is too much power in the other planes. Wise souls descend to learn where doing things is difficult. Once you master how to do where it's difficult, you can use it much more effectively in the higher planes.

Furthermore, those who want to stay below have vast amounts of learning about how to use things effectively. Every so often there is a wonder: a lower plane that has a marvel the higher planes do not, because the lower plane teaches you to use things ingeniously.


The higher power of the higher planes makes them unrestful. If you want a break, you have to descend.


People who can not obtain the high levels, who are weak in some way, can find a place of security in the lower levels.

Families for whom a weak child is a point of danger can send them away for that reason, or so they will not be endangered. A farm where you need powers to deal with the pests, for instance.


A quick look at most of the religious books can help for an inspiration to answer your question: the worldly realm, so to call it, it is the lowest one, inhabited by these fallible and corruptible fleshy beings called humans; yet all the action happens there, the fight between the two sides involved in the book(s) happens for the control of that puny piece of the universe, those pesky beings and their actions.

Have your plane structure be part of some sort of religion where the lowest realm is the battleground for the beings of the higher realms.


Horizontal progression

First, I need to explain some definitions. In games you have two main ways of progressing in power, especially when you speak player level :

  • Progressing vertically. When you gain a level, you get a raw increase in your statistics (health, attack power, defense, ...). At level 1, you can punch a rat to death, at level 100 you do the same thing but to archdemons.
  • Progressing horizontally. When you gain a level, you don't necessarily get more powerful per say, but you get access to new tools and possibly locations (#RewardsOfAccess and #RewardsOfFacility). You could punch before, but now you can make a quick Ki strike to paralyze your opponent, or you can throw fireballs to have the range you didn't have.

Good RPGs always mix a bit of the two in different proportions. As you move on from the village being attacked by wolves to the stage you defend the universe from evil demi-gods, your raw power increases to match up the threat, but you also get new powers with specific uses. Now, as a game-designer of this lit-RPG, you can change the "incline" of your progression, ie. how much horizontal vs vertical progression you get.

Applying this concept to your world

What you want here is a more horizontal progression : People don't become gods at high levels, but they get access to more options allowing them to do more and to adapt to more situations. While a higher-level adventurer is more likely to win against a lower level bandit, they can still be defeated if they're not careful or if there are several enemies.

Universe-wise, the lowest plane will still be a threat to the higher ones, because while they are not as tactically varied, they still get numbers to compensate1. In other words, lower planes will get both political and military power needed to be of interest to higher planes.

This concept is generalizable to every over domain in your lower plane : Getting to higher resources allows mainly to get new options : While your lowest plane will be able to craft potions of cure poison, your higher ones will be able to craft stoneskin scrolls. But you still need to cure those poisons against those sky-snakes. Taming one of the upper plane's griffin allows you to fly, but when you need to break a wall, you'll need the strength of one of those giant rock-bears from the lower plane.

So instead of thinking purely about raw power like most isekai's do, add in horizontal progression. Make your leveling smarter : Don't throw bigger numbers at higher levels, offer new and different opportunities instead.

1: Excepted some specific cases, your RPG should have a higher number of low-level adventurers than higher-level ones. This is both to respect the normal flow of players coming (or being born) and raising up in ranks (or growing) and to be meaningful when you explain what "higher-levels" is.

  • $\begingroup$ In case you want to know more about vertical vs horizontal progression, Josh Strife Hayes has made a quite good point about this for MMOs here $\endgroup$ Commented Sep 30, 2023 at 11:40

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