Nobles are generally divided into two types.
One type is the land-holding Kingdom Nobles.
The other type is the landless Honorary Nobles.
As the name suggests, the former are nobles who have been granted territories by the Kingdom and, with these lands as their base, rule as Lords and regard the development of their territories as their own duty.
These nobles have the right to form Private knight groups, can own armies, and have immense powers; they control all affairs within their territories. Unless they commit a major crime or fail to contribute to the development of their lands over the years, their lands would be taken back and they would be stripped of their noble status. Otherwise, aside from the obligation to give two-tenths of their territory's income to the Kingdom annually, within their land, these nobles' powers are the highest and greatest, with even the Royal Family having no right to meddle arbitrarily.