Is the sword giving you a -1d4 to all rolls, or -1d4 to attack rolls made with the sword? For the first, I'd use a global modifier - turn these on in the Cog icon settings in the character sheet. The global attack modifier section is at the bottom of your Attacks & Spellcasting section. Add a -1d4 modifier and check the box. Repeat the process for the saving throw and skill global modifier fields if the curse affects these rolls as well. If the -1d4 is only for attacks with that weapon, I would just edit that weapon directly: In the Attacks & Spellcasting section, click the cog on the right that appears when you mouse over the weapon. There's a couple of places you can add a bonus for the attack roll, but you don't seem to be able to add dice here, only flat bonuses. So, it's a bit weird, but if you change the CRIT RANGE to this: 20 -1d4cs0cf0[CURSE] that should automatically roll the -1d4 for that weapon. You will still get green crit colouring if the initial die roll is 20, regardless of the 1d4 outcome. I've never done this before - I didn't realise you couldn't add die rolls into those empty modifier fields. This seems very strange.