Kobolds are little freaks of nature. No self-respecting diety would create them to worship him, neither would any mad-scientistish wizard who gets off on splicing pig and elephant DNA.
So where do kobolds come from?
That's easy. One day a really drunk and horny halfling shagged an iguana. 9 months later the sewers of Stormreach are full of Kobolds.
This is why our actions are completely justified in "Purge the Heretics."