Negative Levels

We don't have direct support for negative levels, but it can be simulated via the effects system. From the SRD:

We currently do not have support for skill checks or ability check modifiers, so that will have to be done mentally.
-1 to hit and saves is supported by effects
-5 hit points are done via direct damage via the effect system
The -1 level is not an issue, since d20pro lets you fudge all level-dependent things, such as damage. Just process that mentally.
Spend the highest level spell (if you are using the Spell system in d20pro) - otherwise, just inform the player.

Step By Step
Make sure to click the thumbnails below for full-resolution images.

To create a Negative Level effect in d20pro, select the creature you want to apply the negative level to, then hit the X key or right-click on the creature and choose Alter >> Effect.


Click on the Effect line to input your effects. In the Effect window, choose a -1 to hit and to all 3 saves. Set the duration to 1 day. Also, you can go to the Hit Point tab and click Add Fixed and apply 5 normal damage. If you wish, now is a good time to save the effect so that you can easily load it later.


The effects will then show in the Effect Line. You can still change the name of the actual effect (like Wight negative level, or whatever).


To place multiple negative levels, you can simply re-apply the effect (loading it from the library instead of typing in the values) or create another effect with -2 to the modifiers, calling it Negative Levels (x2) - useful for things like Specters, who apply 2 negative levels at once.

 

Dotting for reference.