Aketon, rules for medieval rpgs

Aketon is a revamp of CHAINMAIL, 3rd Edition, by Gary Gygax and Jeff Perren and OD&D by Gary Gygax and Dave Arneson. It's lighter-weight, but still sturdy, so its no longer like chainmail, its more like aketon.

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This game is more of a supplement, to adapt and play out your other RPG products through this cohesive OSR game engine. Most OSR products can be easily translated into Aketon, just convert the armor over to its rough equivalent, use the applicable weapons, and give spells a partial and full success criteria. Personally, I use Knave 2e spells (INT = 12 for full successes, INT = 6 for partial), but any leveless spell system would work. Bonus points if you pre-write spell failure criteria based on the amount of will they've invested into the spell.

For monster HP, I use monster HD or some equivalent:

OD&D	HP = Total HD
B/X	HP = Total HD
BECMI	HP = Total HD
AD&D	HP = Total HD
AD&D 2e	HP = Total HD
D&D 3e/3.5e	HP = Total HD
D&D 4e	HP = Monster Level/2
D&D 5e/5.5e	HP = CR

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If you want to use spells with spell levels, give the cast +0 to cast level one spells and -X to cast spells over level one where X = the spell's level. If you have cantrips, the cantrip has +2 to cast. Spell levels actually have origins in CHAINMAIL, I only didn't include them because I normally don't use them. Here's a table with what class levels should start getting which level of spells:

Spell Level	Priest Level	Seer Level
Level 1	4	1 and 3
Level 2	8	6 and 9
Level 3	12	12 and 15
Level 4	16	18 and 21
Level 5	20	24 and 27
Level 6	24	30 and 33
Level 7	28	36 and 39
Level 8	32	42 and 45
Level 9	36	48 and 51

I don't know if I'd just give the player spells of that level, but I'd definitely introduce those spells onto the random spell table they roll on when they reach those levels (created by you) and slowly pick off the lower level spells so level 42 Seers don't get stuck with a new level one spell. Especially considering Priests don't get better at spellcasting at the same rate as Seers, so those super high level spells aren't as helpful as lower level ones.

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Included in the tri-fold PDF is:

• Four player classes: Warrior, Priest, Seer, and Thief
• Markets and henchmen
• Domain-level play
• Dynamic combat
• Exciting spellcasting
• Wilderness travel
• Dungeon delving
• A monster creation table

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Aketon was written and laid out by Reese Surles, Art by Inked Gas

Aketon © 2025 by Reese Surles is licensed under CC BY 4.0