What is the Headless Rider in NTE? How to trigger and defeat it?

The Headless Rider is a mysterious world boss/special event in NTE that appears in specific areas of Hethereau. It typically spawns at night (in-game time) near the Old Town district in eastern Hethereau. Trigger: Complete Main Story Chapter 2, then explore Old Town at night for a chance encounter. Combat tips: 1) High mobility with fast charges and AoE attacks; 2) Weak point is the core on its back — dodge behind it to deal damage; 3) Anima-attribute characters have advantage. Drops rare Modules and an exclusive achievement. Team recommended for this challenging fight.