Ok. The issue is you have only the default group setup (which happens to be 'dexterity'). This default is vestigial, from the days before character sheets. Back then, you literally didn't have any attributes and had to manually set them up yourself. I should really take out the default.
Anyway, so I bet your kobold has a dexterity and it is at least a 5. =D What's happening is it is rolling a d20 and adding the value of dexterity to it. That's why you're getting large numbers.
You'll want to remove that default group:
!group-init --del-group 1
Then add something that makes sense. Anymore, that means finding the initiative field on your character sheet (right click the field, view source, copy the name of the input, stripping attr_ off the front of it) and use that. If you're running a custom game system or not using character sheets, there are some options.
Assuming your init mod is named 'init_total', you'd then add it as a group with:
!group-init --add-group --Bare init_total
You'd only need to do this once to setup the configuration.
So, to proceed, what do you use for a character sheet or do you use something else?