False Crystalline sword, where find it ?

Where can I find this sword plz ? And can I put upgrade on it or not ?

I believe you get it from one of Devona's pre-searing quests...or the prize moa bird quest. It's some quest you acquire in Ashford Village.

you get it is presear, it is from the quest for finding the moa bird, I suppose you can add any mods you want to

Yes you can add mods to it. My ele was using one with a 15% enchant mod for a long time until I made a Rago's knockoff.

to think the first time I saw it I though 'ewww!'

i saw a dude selling one in droks with a 20% enchants earlier so yes i assume you can

yes you can mod it
you get it in pre
you must complete the worm problem quest then do the prized moa
i just got one the other day and i dont remember it having the halves casting time but i could be wrong