Castrum Fluminis is way too difficult

[RyuSaarva]

This fight actually isn't hard at all. The only way you would consider it difficult is if 1) you don't know your job's rotations or 2) you are undergeared. I would suggest upgrading your equipment, learning how to play your job and pay attention to the flow of the fight. It's honestly no different from other boss fights.

actually it is hard for a lot of people, it's a very common rage quit duty and I got it countless times when I was still doing mentor roulettes.