The adventure trilogy the above MacGuffin appears in, would seem to suggest that the attack (to the person of wrong religion) is not a function of the sword. Especially because it's also the Sword of Plot Advancement. Though perhaps I should add the option of scaling Weapon's Fury to "of Slaying" with the choices of "Gadianti" and "Zeredite", yeah the second one is a culture not a species but . . .
Anyhow, I was going over professions in HARP, CoM, and the Codex, to see how they'd fit Diomin's theme. Really, I can't think of any profession that isn't appropriate, except perhaps Elementalists. While these two professions are not objectively evil, given the Dark Fantasy bent of Diomin, they'd be associated with evil people: Mystic and Shadowblade. Necromancers tend to generally be assumed evil, so restricting them to the bad guys. Doing the same with Vivamancers, again to fit the theme.