Ye Blue Bookes of danjerus andde koruptynge knowlidge, the finalle tombe of Five Great Wizzards.
A very ornate and very old looking spell book. Chock full of spells, most of which are unreadable by any magic user. The ones that can be read, unfortunately, don’t have the affect the mage is looking for.
A certain type of demon cannot not be hit by ranged weapons or attacks. Attacks have to be made up close and personal for the damage to mean something. Ranged attacks are to impersonal.
Possibally a way to make the ranged attacks more meaningful would be to coat the arrow head or what not with the shooters blood. Of course, they'd better be a good shot, otherwise they're wasting arrows and already bleeding to boot.
Spells: wizards might have half or no effect, preist might work due to divine intention.