how can i kill a horde of greater mummies that just keep using their spells and sending out higher zombies

I assume you are in the room with the clerics of Ilmater

Use fireballs to damage them (use a thief to scout out where they are)
Use missile weapons (acid arrows work great)

I would like to know what your party is like (members and lvl) so I can help better

Here's how i did it

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try only to get one greater mummy at a time, then put your mage (and in my case mage and bard) towards the back of your group, have everyone except them shoot missile weapons at the mummies, then just keep casting fireball, lightning bolt, chain lightening, and Malavons rage that will kill them off fast. Same way to kill the Idol.

<font color = lightgreen>I did it the lazy way: cast Invisibility on my highest-level cleric, then send the cleric in to turn undead. [img]graemlins/petard.gif[/img] </font>

I did the cheater way... sat my Rogue just on viewing range, and cast fireballs just in front of them so they wouldn't agro on me, and just sit and take the damage.. once I got them down to 1 or 2 left I charged [img]smile.gif[/img] (I also ran out of Fireballs hehe)