Not named so because they are any less powerful, just seemingly less involved or followed. Where the Greaters are the seven most worshipped Powers, and the Sisters are the most mysterious, the Lessers lack a story of grandeur. They are because they are. Each governed over things just as important as all others, some even more substantial than others, but that’s all in the eye of the beholder. Falling in suit with the Greaters and the Five Sisters, the generic symbol for the Lesser Powers as a collective is a Thirteen-Pointed Star.
There are technically twelve Powers and one Demi-Power in the Lesser Powers.