it is 100% if someone in party doesn't have it. So if you fight it with like 3 people in party and each of them have the axe already, it wont drop but if you invite just 1 person without it it'll drop. Tested this plenty x;
Overall best axe for ranger. has a better ratio of racc/att over a Kriegs. A fire staff (STR+4Ratt+10) will still beat out this as far as ratt goes unless you combine with Kriegs and get (AGI+5 racc+11 ratt+15) . but imo i'm elvaan and i'll take more agi and racc/ratt than the STR mods(elvaan have highest str). Even if you can't get your hands on a Kriegs main this all the time and sub a Archer's Knife at the least. Its what i've been doing so far until i get my Kriegsbeil.
Many BST would ask, why use this? Factor in the DMG, Delay and TP gain of 7.6% a hit and this is fantastic for BST until Darksteel Tabar +1. Especially nice for BST/DNC.