Man, necromancers can be such a pain in the neck—literally, considering their love for undead minions. The key is disrupting their control over the undead first. Spells like 'Destroy Undead' or 'Turn Undead' are clutch for clerics, but even non-clerics can use area attacks to thin the herd. Necromancers often rely on numbers, so clearing the battlefield buys you breathing room.
Next, target their concentration. If they’re summoning or buffing skeletons, a well-timed 'Counterspell' or a rogue’s sneaky arrow to break their focus can turn the tide. Don’t forget resistances—necromancers love necrotic damage, so gear up with stuff like 'Periapt of Wound Closure' or spells like 'Death Ward.' And for the love of Pelor, don’t let them resurrect mid-fight. Burn the bodies, salt the earth, and maybe bring a paladin for that sweet, sweet smite justice.