Minor gods are those with few worshippers. They are often worshipped locally or their domain is to specific to garner many peoples attention. This category also doesn't include just gods but local spirits, saints and other entities who can accomplish great feats.
As the main criteria for this category of gods are the number of worshippers not all gods in this category are weak. For example, Cirb, the king of sheep, is feared by even the rulers of hell and the true extent of his power is unknown to mortals. However, there are few mortals who make offerings to him and worship him personally as he is more so seen as an appendage to the goddess Brigid instead of an individual god of protection. This means that most people who need protection will worship Brigid and not him.