Expand Weaknesses

Unofficial homebrew option, off by default. Turn it on in Settings under GM Tools.

When enabled, the Encounter Builder adds thematic damage-type weaknesses to creatures that the official rules leave bare, so varying your damage types matters more often at the table. About 1 in 5 monsters gains one.

The value scales with the creature level: roughly 5 at low levels, 10 at mid, and 15 at high. Only creatures with a fitting theme get a weakness, and a type is never added if the creature already has it or is immune or resistant to it.

It is display-only and never edits the underlying creature data, so turning the setting off restores every stat block exactly.

What it adds:

• •Skeletons → bludgeoning
• •Plants, mummies, vampires → fire
• •Undead → vitality
• •Incorporeal spirits → force
• •Fey → cold iron
• •Aquatic, metal, and clockwork creatures → electricity
• •Cold-blooded reptiles, insects, and oozes → cold
• •Fire creatures → cold, and cold creatures → fire
• •Earth and stone bodies → sonic
• •Airy or gaseous creatures, swarms, and troops → area and splash damage
• •Trolls, shelled, and coral creatures → acid
• •Shadow creatures → light

GMs can add their own entries by editing public/data/expanded-weaknesses.json.