Drafting Alternate Grenade Rules (With An Example For Starfinder)

Grenades, and explosives in general, are tricky to write rules for in most d20-based ttRPGs. If a grenade isn’t effective enough, it feels more like a firecracker than a deadly weapon of war. If it’s too effective, it can end encounters so quickly it’s no fun for the players, or accidentally wipe out PCs in undramatic ways.

When grenades show up in action/adventure fiction, they tend to act less as damaging devices than plot devices that force people to seek cover. The threat of them is generally represented not by them killing main characters, but by forcing characters to take them seriously and possible shake off effects of shock and awe.

(Grenade art from the public domain)

Example: Starfinder Revised Grenades

So, let’s try to model that behavior, specifically for Starfinder. Within that game, grenades are pretty expensive consumables anyway, so a power-up shouldn’t break the game even if it makes grenades more affective and appealing. That said, if these seem too powerful, you can limit these rules to actual purchased consumables, rather than spells and class features that allow characters to create or emulate grenades without a credit or OPB cost.


Grenades are dangerous, deadly military explosives that everyone must take seriously as a threat, no matter how tough or resilient they are. While savvy and active combatants know to duck for cover and shake themselves free of the shock of battlefield explosions, doing so comes at a cost.

When you fail a saving throw against a grenade that has an item level no lower than your character level/CR -2 that deals damage (as opposed to, for example, smoke grenades), you must either expend a Resolve Point or be staggered on your next turn. This represents the need to duck, take cover, and shake yourself back to focus after narrowly avoiding more serious injury.

Helpless characters that fail a save against such a grenade treat the attack as a coup de grace against them. As a full round action a character can make an Engineering check (DC 15 + 1.5x grenade item level) to wedge a grenade into an adjacent stationary structure or unattended object, causing it to do max damage and have only half its normal explode radius. On a failed check, the grenade explodes in the character’s hands, and they take max damage.

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About Owen K.C. Stephens

Owen K.C. Stephens Owen Kirker Clifford Stephens is a full-time ttRPG Writer, designer, developer, publisher, and consultant. He's the publisher for Rogue Genius Games, and has served as the Starfinder Design Lead for Paizo Publishing, the Freeport and Pathfinder RPG developer for Green Ronin, a developer for Rite Publishing, and the Editor-in-Chief for Evil Genius Games. Owen has written game material for numerous other companies, including Wizards of the Coast, Kobold Press, White Wolf, Steve Jackson Games and Upper Deck. He also consults, freelances, and in the off season, sleeps. He has a Pateon which supports his online work. You can find it at https://www.patreon.com/OwenKCStephens

Posted on September 5, 2022, in Game Design and tagged , , , , . Bookmark the permalink. 1 Comment.

  1. I love that alternate rule. Grenades always felt not very dangerous and overly expansive in our games. This staggering effect makes them much more interesting in play again.

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