Where is the skill trainer that has Nightmare Weapon?
I've checked Shing Jea and Mainland Cantha, but I'm not seeing it.
Ritualist skill Nightmare Weapon skill trainer
chumsy
icedragon981
I checked Guild wiki and it says "This skill is currently unavailable from Michiko, the Skill Trainer in Kaineng City. It can be obtained from skill trainers in other towns, however, such as Yokuni in Maatu Keep." So I'd assume that you'll need to get further in the story to get to the skill trainer that has it.