The ratfolk example on page 21 is paying too much for its abilities. If they come from the Darklands, you can substitute Underground Sneak on page 14 for the three Skill Bonuses. That makes them even better at sneaking and leaves them 1 RP to buy either Bite or the Stalker ability. If you're making them from the Darklands, you could make them Vulnerable to Sunlight, give them both Bite and the Stalker ability, and improve the size of the Bite attack one category.