Tactics schamctics bah!
All you need is a good tank (i.e. I use my main char, human berserker), good weapons, Boots of Speed, Oil of Speed, few bottles of Potion of Genius and 'that-other-one', which gives +3 INT/DEX. Slap on boots, quaff potions, kick open the door, scream
"Surrender fools!" and let the whooping begin! Add Enrage as a spice on top too.
Works every time! If INT is getting lower, quaff another Potion of Genius and 'that-other-one'. That way I could keep my INT all the time at the base level - they take it down, potions get it up, soon the 'drain' icon goes away and I have INT even higher and so on. My lovely "you know what" katana stuns them as well and they die like roaches. You can rotate the targets, i.e. as soon as one is stunned, switch to another to stun and so on, then back to first. Look at the fireworks and foe shaped chunky bits. Works every time to me heheh