Dwarves in LotR are short, aggressive, and bearded. As a race, they are known as fine warriors and craftsmen, but motivated mainly by personal gain and greedy of material wealth. They are extremely secretive about their culture, rarely speaking their own language in front of others and never giving out their real Dwarvish names. Unlike Men and Elves, they were not created by Ilúvatar, but by Aulë.
Individually, most named dwarves are known to be honourable and courageous while some few have been villains. Notable dwarves include Thorin Oakenshield and his companions, whom Bilbo Baggins accompanied to the Lonely Mountain, and Gimli son of Glóin, the sole dwarf member of the Fellowship of the Ring.
Prior to the release of the Hobbit trilogy, dwarves were generally cast as Designated Misogynistic Bastards or forgotten entirely, because they were not perceived as attractive. They were incredibly resistant to Mary Sue–influenced lust, to the point where Mary Sues and Suefluence did not repel them, but they repelled Mary Sues. This curious property is what prompted the research and development of the medication Anti-Lustin, which was originally derived from dwarf blood samples.
This appears to have changed to at least some extent with the release of Peter Jackson's The Hobbit, as Sues now often go after members of Thorin's Company. Thorin, Kili, and Fili in particular are regarded as Lust Objects.
LotR dwarves as PPC agents are very rare, but there are a few, the most notable being Justin Agent. Like Justin, they rarely use their real names due to their secretive natures. They usually take their names from the languages of Men living near them. This tendency is evidenced perfectly by Agent Jane Doe.