I like very much this kind of weapons that debuff enemies in combat, like Plegian Axe and so on.
But I have a question before giving this weapon (or not) to my Caellach (I think it fit very well with him, he is a desert warrior after all).
Does this weapon work with visible or invisible buffs?
If it works with invisible buffs, then does it apply directly -15 ATA/DEF to enemy if Caellach is not adyacent to an ally? Thats pretty insane (-5 Ata /def x 3).
With Lull skills + Solo skills it would make a interesting combo.