The Affront is an Involved species from the moon Issorile. Once known as the Issorilians, they were given the "Affront" moniker by the Padressahl in reference to their exceedingly brutal culture.  The Issorilians enthusiastically adopted the nickname and have used it ever since.
Finding a MentorEdit
The Culture was aware of the Issorilians many centuries before Idiran-Culture War and sought some way to improve the Issorilians behaviour. The civilization was not only aggressively expansionist, but had a culturally and socially ingrained traits for exploitation, sadism and brutality.
Maintaining contact and relations was difficult since the Issorilians treated technologically more advanced civilizations with suspicion, and the reverse with contempt. Eventually, the Culture found the Padressahl in the same volume of space as the Issorilians; the Padressahl had a similar evolutionary history and physiology as the Issorilians and so more likely to be accepted, but they also were closer to the Culture in terms of moral outlook. The Culture appealed to the Padressahl to guide the Issorilians.
The Padressahl accepted. Early attempts were rocky. During one episode a Padressahl trade delegation was eaten, prompting them to nickname the Issorilians the Affront. Ironically, what was intended as insult was enthusiastically embraced by the Issorilians. They began calling themselves the Affront and refused to drop it even after relations with the Padressahl improved. The Padressahl continued their mentoring role for many centuries. With the Affront being handled, the Culture was free to engage with other nearby civilizations.
Dealing with the GalaxyEdit
However, a century or so after the Idiran-Culture War the Padressahl suddenly sublimed. The Affront was freed to harass neighbouring civilizations, including those being shepherded by the Culture and others everyone had not seen fit to contact yet.
Now the Culture, and the other Involveds, had to deal with the Affront themselves. Eventually the Affront was convinced to abide, at least most of the time, by the generally accepted code of conduct for an Involved. This was after considerable effort, outright bribes, and allowing the Affront to "covertly" steal technology. The rate of expansion onto other planets was slowed when they received orbital technology form the Culture; the Affront refused to accept pre-made orbitals. The Culture hoped technology transfer would undermine some of the less desirable traits of Affronter culture and society.
After the Idiran-Culture War, the Culture was not willing to entertain another massive military action to contain the Affront (even though it was at the height of its military power). Clandestine efforts to moderate their society did however continue, and after the Affront's warlike actions in Excession, the Culture started more direct steps in limiting their expansion and behaviour.
Society and CultureEdit
Affront society is described as being "a never-ending, self-perpetuating holocaust of pain and misery", where the strong prey upon weaker species and individuals. Among the Affront's technological accomplishments is an aptitude for genetic engineering, which they developed long before spaceflight. They use this skill almost exclusively on 'prey species', which tend to be changed so as to provide greater sport (and opportunity for sadism) during the communal hunts forming a major part of the Affront culture. Some examples of these changes include altering game animals to experience heightened levels of fear when recognizing the silhouette of an Affronter, or altering beasts of burden to panic when their masters are excited and thus induce them to pull vehicles faster. One of the few changes to their own species was the redesign of their females to make sex painful for them, a choice exemplary of the reasons they are considered abhorrent by the Culture. "Progress through Pain" is a common Affront slogan.
The Affront pose a difficult moral problem for the Culture with its reluctance for direct intervention. However, the Affront are intelligent and cooperative enough (ritual or spontaneous duels notwithstanding) to build a stellar empire, and to develop advanced technology, or else steal it. They have also received some Culture technology (such as the ability to build orbitals) in exchange for grudgingly kept promises of better behaviour.
An average adult Affronter's body consists of a bulbous mass about two metres in diameter, which hangs from a frilled gas sac one to five metres in diameter depending on their desired buoyancy and which can be deflated and covered by protective plates. Six to eleven tentacles of varying length and thickness grow from the central mass, of which at least four end in leaf shaped paddles. Many Affronters have lost one or more tentacles in combat or duels. Beaks on the front and rear of the central mass cover the creature's mouth and genitals, respectively. The eyes and ears are held on stalks above the fore beak (they also have a sensor bump atop the gas sac). An anus/gas vent is located in the bottom centre of the main body. The latter is one of their sources of propulsion, though they usually 'walk' on their limbs or 'paddle' through the air unless in a hurry.
Their homeworld is described as a 'fog-bound moon-planet', probably similar to a larger version of Saturn's moon Titan. Affronters require a high pressure, low temperature environment, and breathe an atmosphere composed mostly of nitrogen and methane, plus other trace hydrocarbons.