The Long Slog

More formally known as the Anogoul / Demex war. This war has been ongoing for almost thirty years. This is only a handful of years less than the age of the Anogoul nation. Demex claimed this territory even without ever having policied or utilized the territory at all.
Most of the time this conflict has been a series of skirmishes, localized battles, and stalemates. Most offensives are initiated by Demex, and Anogoul has been hard at work perfecting defenses. Anogoul has primarily sought to take out leadership in the Demexian forces as well as cripple supply lanes to the various war fronts.
Luckily Anogoul receives help from other nations and is protected by a series of natural features and phenomena. The land border between the two is miles of heavy bog lined with carnivorous plants, disease-ridden insects, and dangerous traps set by Anogoul. This makes significant inroads by land very difficult for Demex. The ports of Anogoul are deep and often flanked by tall rocky outcrops lined with defenses making direct navel incursions difficult.
The last major advantage of Anogoul is that Demex is not fully committed to the war. They have other priorities in the Jade colonies and other projects that preclude them from just overwhelming Anogoul by force. They refuse a truce or to make peace, leaving one or two generals using this as their pet project and hobby war.
Typically casualties in skirmishes skew from two to four dead in the Demex forces for each Anogoul soldier killed. This disparity is due to a more collaborative approach to focusing on clear goals instead of the Demexian desire for personal boasting and honor-winning. This cohesiveness helps greatly in preventing losses like the Demexian forces have. That being the case, Anogoul feels like it is constantly fighting for survival against a much more powerful force, and they are right. It is a constant looking for new defense and strategizing how to strike back meaningfully at Demex without actually angering the central leadership.