The Eagle Tribe is the Mongol force that has taken Iki Island, led by the shaman Ankhsar Khatun, called the Eagle. They are the main enemy of the Iki Island expansion, and their purple-uniformed troops bring units you never see on Tsushima.
The tribe invaded Iki apart from Khotun Khan's army, mixing veterans in Tsushima's colours with its own purple troops. It also sent raiders to the Toyotama coast, which is how Jin first learns of it.
Kill shamans first, because they double the health of everyone nearby. Track a switcher's weapon and change stance with him. The double-bladed brutes shrug off Moon Stance, so rely on dodging and Ghost Weapons.
Khunbish beats Jin at Fort Sakai and the Eagle forces her medicine on him. Jin later retakes the fort with Iki raiders and kills Khunbish. The Eagle makes her last stand where Jin's father died and loses a duel to Jin.
Shamans
Shamans are Eagle Tribe support units on Iki Island who stay at the back and chant to power up nearby Mongols. Buffed soldiers get double health and turn far more aggressive, so the shaman is your first target.
Switchers
Switchers are purple-tier Eagle Tribe soldiers on Iki Island who carry several weapons and swap between them mid-fight. You have to keep changing stance to match whatever they are holding.