New training spots? Bosses? Useful quest lines? New equips? What level for all of these? Also just got to 3rd job on my xbowman, is anything there of interest to a lvl 70?
The castle has some decent training spots for late 1st job, mid 2nd job, early and late 3rd job, but I haven't personally tried them for exp/hour rates on different characters. I'd think that mobile/ranged characters will enjoy the maps more than melees would, because the maps are mid-sized and the mobs are pretty spaced out on various little platforms. The area comes with an Anego counterpart in Kacchuu Musha that does more damage and can't be pinned like Anego is, and it's on a longer respawn timer as well. The Kacchuu Musha etc allows you to summon a 1/day boss called Castellan with just over 1b HP that gives a really good amount of exp and drops some unique items - an untradeable eye accessory with base STR and LUK (1-3) as well as some jump and avoidability and 3 slots clean, and also drops the Elemental Wands+Staves. The drawback of the boss is that it's on a quite high HP requirement of 15.6k (unavoidable) for the second body (only about 12.5k on the first body) and to get to the boss map requires going through a quite frustrating jump quest which cannot be skipped. Other than the Castellan drops, there isn't much other interesting to note - one mob drops Shield Watk 30s, I think, and another drops Ilbis. Might have forgotten something, but the area is mostly an exp zone with little other appeal outside of a few short questlines.
Also, does that mob actually drop the shield Watk 30s? someone (nesi i think?) was saying that a couple of the scroll drops in ninja castle have been removed cause too OP