Xenosaga's KOS-MOS Appears As A Rare Blade In Xenoblade Chronicles 2 - Siliconera

Nintendo revealed the very last Rare Blade on Xenoblade Chronicles 2’s official Twitter account and they saved a big one for the final reveal with KOS-MOS from the Xenosaga series.

KOS-MOS, Xenoblade Wiki

Switch - Xenoblade Chronicles 2, Page 2

Xenoblade Chronicles 2 - The RARE Blade compilation (OP to be continuously updated)

Xenogears and Xenosaga Study Guide: The History of Xenosaga

Switch - Xenoblade Chronicles 2, Page 2

KOS-MOS, Xenoblade Wiki

Tetsuya Takahashi (director of Xenoblade, Xenogears and Xenosaga) holds an interview with the Persona series' director Katsura Hashino on Xenoblade 2's game development. : r/Games

KOS-MOS, Xenoblade Wiki

Xenoblade Chronicles 2, Xenoblade Wiki