The Chainelane Isles is a region in the deep periphery spanning some 100 lightyears and situated 100 lightyears coreward of the Greater Valkyrate. Described as a "miniature Inner Sphere", the Isles are not a unified realm but instead are home to numerous small duchies or principalities. Like the successor states of the Inner Sphere, these neighboring principalities constantly vie for supremacy and have been fighting Succession War-style combat for a long time.
Though BattleMech technology is present within the Isles, none of the Chainelane Isle states are able to manufacture their own BattleMech forces. 'Mechs were rare and prized assets much like in the lostech-ridden Succession Wars era of the Inner Sphere. Each nation within the Isles also deals with traders upon chance encounters, and attempts to acquire modern technology. Because the states of the Chainelane Isles rarely acquire the technology required to significantly turn the tide of war, wars within the Isles are fought almost exclusively by infantry and conventional armor. Though warfare within the Isles may be grinding upon the combatant armies, the collateral damage caused by this warfare is minimal at most, and few borders change within the Isles.
During the Clan Invasion of the Inner Sphere, the Chainelane Isles stood in the path of the Clan juggernaut. However, only the Duchy of Vendôme's military effectively disappeared "overnight" within the Isles. This led to speculations by ComStar that the Clans may have tested their mettle on an "Inner Sphere" opponent before reaching the Inner Sphere's periphery border.
In 3055, conflicting mercantile interests between Clan Diamond Shark and the Hanseatic League resulted in skirmishes near Chainelane space. Though the Diamond Sharks defeated the Hanseatic CPF, trade has not diminished between the Hansa and the Isles.
At the dawn of IlClan Era, after the Hanseatic Crusade, the Cluster saw a short fight between the Escorpión Imperio and the now renamed Clan Sea Fox, but later, after the victorious Scorpions established a enclave there, both clans agreed to share patrols in the area, and the Imperio also began building HPGs in the area.
Each planet is controlled by several factions.
- The Periphery, 2nd Edition, pp. 91–92: "The Chainelane Isles"
- Explorer Corps, p. 57: "Chainelane Isles"
- Handbook: Major Periphery States, p. 10
- Spotlight on Hellion Keshik, p. 4