Some Harnessers have multiple Harnesses in the form of a Harness class. Most have single-element Harnesses, but one can obtain another element through a process called Inheritance, in which one Harnesser passes a single Harness to another person. Harnesses are broken up into classes in which single elements are classified into groups. Some single-element Harnessers make a point of creating "clans" to form a full Harness class. The Borealis clan is an example of this system.
The so-called "main types" of Harness classes are Sky , Earth and Life . Together, they are able to manifest all the worldly elements. They are, however, more or less extinct, as only one or two Harnessers with the respective classes are still alive in the world today.
There are many kinds of Harnesses with names to differentiate certain types. Other than Sky, Earth, and Life, it's not terribly uncommon to see Harnessers who possess complete classes that are the world's elements, but it's not common either.
There are such things as unworldly Harnesses (aptly named Unworld Harnesses), those of which control elements that are, obviously, not of the world's creation.
Because of the different Harness combinations, classes were created. Classes are basically groups of single Harnesses in one. They include up to 3 Harnesses--Life is the only exception to this rule for unknown reasons. The list of classes below is not a complete one, as there are many combinations that one Harnesser can have. It simply details those that have been officially recorded and named. More information on each class can be found in different entries of the encyclopedia under their recorded titles.
Sky [ wind, sun, & lightning ]
Earth [ nature, ground, & magma ]
Life [ telepathy, telekinesis, water, & nature ]
Storm [ lightning, wind, & water ]
Brimstone [ heat, fire, & magma ]
Beryl [ water & ice ]
Cloud [ wind & water ]
Luster [ metal & lightning ]
Mind [ telepathy & telekinesis ]
Survival [ nature & fire ]
Unworld [ space, time, gravity, & undead ]