How I Build Balanced D&D Encounters with CharGen's Monster Generator

I build encounters for a mix of players, and the one thing I want is consistency. I want the fight to feel dangerous without blindsiding the party, and I want the monsters to belong in the scene. The official 5e encounter guidelines spell out XP thresholds and multipliers, but the work of turning those into a specific monster with a place in the story still takes time. My answer is to keep the rules in my head and use CharGen's Monster Generator to do the heavy lifting.

This post is my practical workflow. It is not a sales pitch. It is the short list of settings I actually touch and the bits I ignore. If you have ever stared at a Challenge Rating table with a half-written idea, this is the method that gets me to a finished encounter quickly.

The problem I am solving

There are two parts to encounter prep that most guides split apart: mechanical balance and narrative fit. The official rules focus on XP budgets, monster multipliers, and party size adjustments. Those are essential. If you do not use them, you are guessing. The issue is that the rules do not write the monster for you. They do not give you the flavour, the role, or the reason the monster is in the room. That gap is where I lose time.

I do not want to spend twenty minutes on a stat block and then another twenty minutes trying to make it feel like it belongs in the story. I would rather spend that time on the hook, the setting, and the aftermath. The generator lets me get a credible monster quickly, then I tune it in a way that fits my table.

Where I start in CharGen

I work from the RPG Workshop because it keeps all the generators in one place. Go to the RPG Workshop page and use the left-hand list titled Generators. You will see items like NPC, Monster, Shop, Tavern, Faction, Loot, Settlement, Region, and Poetry & Lore. I pick Monster, which switches the form on the right to the Monster Generator.

If you prefer a focused view, the Monster Generator has its own dedicated page too. I still like the workshop because it makes it easy to jump to NPCs and Settlements after I finish the encounter.

The three fields I always fill in

The Monster Generator gives me three required fields that matter for balance.

Quick Description (Optional) This is a short prompt. When I leave it blank, I get something fully random. I almost never leave it blank. Even a line like “tide-warped eel that drags sailors into a whirlpool” gives the generator enough direction to give me useful flavour. I keep it tight and concrete so the output stays anchored.

Challenge Rating This is the backbone of encounter balance. I use the official 5e encounter rules to decide the target CR. The Basic Rules use XP thresholds by party level and then apply multipliers based on the number of monsters. The multiplier matters more than most people think. A bunch of small creatures can be tougher than a single big one because of the action economy. When I pick CR, I pick it as part of that calculation, not as a separate creative choice.

Game System The default is D&D 5E and that is what I use most often. If I ever run another system, I switch it here so the generator gives me stats that actually make sense for that ruleset.

Those three fields are enough to generate a monster, but the optional settings are where the encounter starts to feel tailored.

The optional settings I actually use

The optional settings live behind the Show Optional Settings toggle. I do not touch everything. I use the fields that let me control theme and difficulty without adding work.

Monster Type This is where I decide whether I want a beast, fiend, undead, or something else. If I am reskinning a familiar creature, I still set a type because it drives resistances and the tone of the write up.

Combat Role This is how I make the fight interesting. A brute feels different from a skirmisher. A controller changes the pacing. I often use this to shape the encounter without messing with CR.

Size I treat this as a visual lever. Size tells the players what to expect before initiative even starts. A huge monster sells itself. A tiny monster can still be deadly if the role is right.

Environment This is the most important flavour field. If the monster belongs in a frozen ruin, I say so. If it is a swamp threat, I say so. This field makes the description feel like it grew out of the setting instead of being dropped in.

Party Level I enter this when I want the generator to match the tone of the encounter to the party. It is not a replacement for CR, but it helps tune the output towards the actual party.

Difficulty I use this when I know the tone of the fight. Easy is for a warm up. Hard and Deadly are for set pieces. I keep it honest and do not overuse it.

Reskin Of This is the sleeper setting. If I know I want something that behaves like an owlbear but looks like a crystalline lion, I put “Owlbear” here and describe the crystals in Additional Details. It saves me time and still gives me a unique creature.

Additional Details I use this to add personality, tactics, or a single standout ability. It keeps the output consistent with my setting without rewriting the whole monster.

How I balance the encounter quickly

I use the Basic Rules encounter guidelines as my sanity check. The rules use XP thresholds based on party level and apply multipliers for the number of monsters. That multiplier is what turns a balanced fight into a wipe if you ignore it. I usually build backwards. I decide the number of monsters and the sort of experience I want, then pick a CR that lands in the right range. Once I have a target CR, the generator can do the rest.

If I want a single boss, I will set a higher CR and lean on environment and tactics to make it interesting. If I want a scrappy fight, I will use a lower CR and then add two or three extra creatures, knowing the multiplier will push it into the right band. That is the rule of thumb I use most often.

Example: a river shrine ambush

Here is a recent example. The party were tracking smugglers along a river and stopped at a ruined shrine at dusk. I wanted a quick, tense fight and a creature that felt linked to the water.

I opened the RPG Workshop, selected Monster Generator, and entered this:

Quick Description: “A river spirit twisted by oil, dragging travellers into dark water”
Challenge Rating: 3
Game System: D&D 5E
Monster Type: Elemental
Combat Role: Controller
Size: Medium
Environment: River, marsh, flooded ruins
Party Level: 3
Difficulty: Hard
Reskin Of: Water weird
Additional Details: “Leaves a slick on surfaces; can extinguish torches; whispers like running water”

The output gave me a monster that felt on theme and had mechanics that matched the scene. I did not need to change much. I adjusted the descriptive text to fit my shrine and called it done.

I keep flavour tight and readable

The generator can produce a lot of flavour text. I keep only what I need at the table. If I cannot imagine saying a sentence out loud during play, it does not stay. For example, I keep the monster’s tells, its movement style, and a signature ability. I cut long lore sections unless they matter to the story.

This is the part where I stay strict. The best encounter prep is usable at the table. Short notes, clear mechanics, and a mental image. Anything else is for later.

The role of AI debates in how I write prompts

AI tools are in the middle of serious legal and ethical debates, and I keep that in mind. There have been high profile copyright lawsuits against AI companies, and the legal landscape is still changing. That matters for fantasy work because it is tempting to type a famous creature name or a recognisable character and hope the model fills in the rest. I do not do that. I keep my prompts original and describe my own concept in plain language. It keeps my work clean and it keeps the output more distinctive. For context, Disney and Universal sued Midjourney for copyright infringement, and more studios are now joining those cases.

For monsters, this is easier than it sounds. I use physical traits, behaviours, and environments instead of proper names. “Glittering glass scales, blind eyes, and a hunting call that cracks stone” is more useful than a named creature anyway. It makes the output mine.

When I use the dedicated Monster Generator page

If I am writing an encounter-heavy session, I stay in the RPG Workshop. If I need to focus on a single creature, I jump to the Monster Generator page and keep the space clean. Both routes lead to the same place, and I do not get precious about it. The important bit is the field choices.

My practical checklist

These are the steps I follow every time:

Decide the feel of the fight and the number of monsters.
Use the encounter rules to pick a target CR band.
Go to the RPG Workshop and select Monster Generator.
Fill in Quick Description, Challenge Rating, and Game System.
Open Optional Settings and set Monster Type, Role, Environment, and Difficulty.
Use Reskin Of if I want a familiar base with a new skin.
Add a single clean note in Additional Details.
Generate and trim the output to table-ready notes.

What this saves me

I still do the creative work, but I do it in the right order. I start with balance, shape the flavour, then cut the output down to what I will say at the table. That is the difference between a prep session that drags and one that ends with energy.

The Monster Generator is not a replacement for rules knowledge. It is a fast way to apply the rules without getting lost in busywork. That is why it works for me. If you already know your table and you already know the feel you want, the generator gets you to a finished encounter quickly, and it leaves you time for the part that makes the session memorable.

If you want to try the workflow, start with the RPG Workshop, pick Monster Generator, and be strict about the fields you touch. It is the shortest path I have found from idea to playable encounter.

Image credits:

Hero and supporting images generated with OpenAI Images (gpt-image-1.5) for this post.