TLDR; The session was tons of fun, and I have a ton to learn still, but my party enjoyed it and want more! Aaand I’ve added a lot of thoughts and drawings around the session here.
Just wanted to share my experience as a new GM; I did it! I ran the first session with my demon-themed campaign! Before this, I’ve been a player in Pathfinder, DnD, Tales from the Loop and Star Wars campaigns, currently in a 1 year long DnD campaign. Not as much as some of you, but it’s been enough to make me wanna try GMing for a while. Enter ICRPG and Runehammer, and here we are. 
The session was held online. And against my best judgement, my group consists of 5 PCs - people I’m quite comfortable around to begin with. I figured since it’s turn-based it shouldn’t pose too much of a problem, and it really didn’t.
I’m trying to gather the “short” version of my process here, which started half a year ago or so, when I started getting inspired. But I only started preparing in November/December I think.
About the campaign
We’re in the Demon Realm. A high-fantasy place where demons live. Demon Lords rule territory, each different from the other. Despite their differing appearances, there are still some recognized archetypes:
The hunters (brute force)
The seekers (magically adept; blind but can see magic streams)
The shadows (dexterious, can merge into the shadows)
The winged (strongest archetype, some can turn into dragons)
Our players find themselves in the service of Demon Lord of the Great Forest, Fernaghyr (generally referred to as Demon Lord Fern). Here’s an early sketch of him, as well as his most trusted bodyguards:
They’ve been recognized as individuals with potential, and have been recruited into a special force-in-training under a winged commander, Draukh.
Tabletop Simulator
I decided to run the campaign in Tabletop Simulator since everyone had it, and it just gave me an overall good impression when it came to freedom and customizing. I’ve found that adding everything as cards is a great way to add things in bulk! Be it cards, tokens or maps, they all work great with the format since cards support transparency. I ended up with a combination of custom drawn maps and images from Unsplash to set the mood in case I wanted some theatre of the mind.
Bonus: Cards can be flipped, so adding a death state for enemies and players alike was simple. Luckily one of the players had already used it to setup DnD sessions, so I got some neat tips here and there. After some tweaking here and there, it’s starting to look pretty neat!
A shot of the table setup:
Characters
I volunteered to draw my party’s characters because I love these kinds of things. I got permission to create all but one character (the one in heavy armor). I love making character designs, so I had a lot of fun with it. Making tokens for the board, I color-coded them with yellow for allies, blue for the PCs and red for enemies.
I didn’t have enough time/energy to create tokens for all enemies and NPCs, so my quick fix was to make placeholder enemy and ally tokens. My goal is to not have to use them, but they took off a lot of pressure for me in the meanwhile!
Initial sketches for character presets:
The main enemy of my one-shot, lady Teranoir:
Takeaways
- I’m very glad I did a session zero beforehand, where we went over character creation, the group and the basic mechanics. Even though I had to recap some of it today, people grapsed most of it quite fast.
- Although I probably overprepared, I’m glad I did! It was a lot of fun and helped me coming up with things on the spot.
- Adding custom skills is easy, and can add personality to characters.
- Tabletop Simulator: Adding items to player inventories beforehand is a smart thing to do (I forgot and spent almost an hour fixing it with my group). Adding loot as cards could also be an idea (can then shuffle and place cards when a player tries looting).
- Temporary cards are great to use in a pinch, but it takes time writing…
- Cards for items is a nice touch for the players. Icons per category can further improve quick scanning for equipment, skills and consumables.
- I absolutely love card type tokens!
- My time estimates were way off, and I only ran part 1/3 today. So my one-shot will probably last one or two more sessions.
I learned a lot from this session. The players were also nice and patient with me, and seemed to enjoy themselves. This was originally intended as a one-shot that would be concluded this session, but we spent all our time on the very first map! They fought against another demon group, the mountain tribe; Humanoid goat demons with goat eyes, horns and hooves. And at the end, they wanted more!! So we’ll have another session next week to continue 
They also seemed to enjoy the NPCs I made. Since I forgot to let them pick a class item at the start, I instead treated it as a reward after the combat! Enter merchant Larce, selling these items at such a high price that the players couldn’t afford them, but commander Draukh of course offered one to each player, since “They had a lot yet to learn before they would be ready as a group”, which was met with laughter from the group. 
For the next session, I’ll create a HQ for them and give them each a room because I can. They’re gonna feel riiight at home. Draukh will assign the rest of my one-shot as a rescue mission, and Larce might be visiting with new items to sell. Potions, food, maybe some better items?
It might not be a one-shot anymore, guys…
