I’d do something like this for WL2-shadow2 with that build: https://rjgtav.github.io/tos-database/simulator?tinyurl=y8vxppq8
-Lethargy is a good 1-pointer, it increases magic circle damage by 35%(if you buy the attribute), and also doubles earthquake damage.
-Unbind is not really needed. Or at least, I’ve never found a good use for it.
-Dark Theurge is a 1-pointer too. You only use to quickly buff yourself with Drain, not for damage.
-Mastema is must max imo.
-Invocation was nerfed a while a go, I don’t think its that good anymore. I’d rather get max Pole of agony.
Other than that, your skill distribution seems good to me.
In regards to the FF1, if your party has a FF3 then yeah, your FF1 rank is not really useful.
I play Wiz3-Ele3-FF1-Shadow3, its pretty good, can even run velco as Dps. Has decent AoE and great single-target dps. I had to put 100Spr to help with the Sp usage though, Int shadowmancer drains your sp very fast.
With a good party, each Shadow thorn 15 can do cap damagex2 even on World bosses and velcoffer.
Link to my build: https://rjgtav.github.io/tos-database/simulator?tinyurl=y9zvwrx6
The main complaint I have about Shadowmancer is that the costume minigame is way too hard, took me 6 months to get the special effect lol.
/sorry for the wall of text