How to kill Lord Dredmor?

Solution 1:

I managed to get to the bottom of the dungeon and off Dredmor on max difficulty with permadeath on. I documented my entire strategy here, but I'll summarize as best I can.

I suggest you grab the expansions if you can, it's only a couple of bucks and it adds some new stuff that is worth having. That said, don't turn on the Diggle Gods levels, and don't take any portals to the Wizardlands, as both of these are just going to increase the odds of you biting it.

My skills were:

Master of Arms, Perception, Burglary, Unarmed Combat, Battle Geologist, Alchemy, and Smithing.

Battle Geologist requires an expansion, and Smithing was kind of underused in this build, so I provided some backup skills for your consideration in the full guide. I'd almost suggest a ranged weapon tree of some sort.

This is a very "tanky" build, where you're going to focus on defensive stuff. Dual wield shields, and focus on Block, damage resistance, and elemental resistance. Learn to exploit the AI to trap it in corners and halls where the enemies can't surround you. This will get you through the majority of head-on encounters.

For very deadly fights, especially against magic users, (such as Dredmor himself), you're going to want high amounts of sight radius. If you can find a spot where you can see these guys at range but they can't get close to you, you can plink away at them with thrown weapons or crossbows. Failing that, the Perception tree's Eye Lasers do decent damage, and they don't require mana to use.

You can also use Burglary's Lockdown ability at range to hold them still and get away if things are looking bad. Burglary's "Lucky Pick" ability also means you can close all doors (ie, you're not bashing down locked ones when you're out of picks), so prepare to immediately close doors once you open them. Finally, save items of invisibility, which are good "panic" abilities to have on hand when you're at the final level.

Solution 2:

Dredmor's melee will instantly kill most characters, so don't go toe to toe with him unless you can 100% avoid his attacks (Swashbuckling etc).

You can silence him to avoid his devastating magic, but then he'll charge towards you continuously.
In this case, you need something to keep him away from you: teleports, knockback (which he may resist) and obstacle summoning all work. Pets can distract him, but they'll likely die in one hit too.

Righteous, acidic, aethereal and piercing damage are as close as it gets to Lord Dredmor having a weakness. Astrology, crossbows and roguish science are all fairly effective skills.
Fire/ice/lightning, putrefication and slashing work decently too, but he's nearly immune to the rest.
He has a lot of magic resistance and good armour, so try to debuff that.

There's several items for any character that can make a big difference.

First off, you should use a voltaic potion or Wand of Tesla before the battle, since the resistance helps against Dredmor's biggest spell (Thor's Fulminaric Bolt). Fulminaric Bolt may still kill you, but you're much better off having that resistance.

Sonic wands are a very common source of silence, but the debuff only lasts 8 turns.

Mirror shields will save you from his projectile spells; for extra fun, dual wield them.

If you decide not to silence him (so you're safe from his melee attacks), you need a lot of health, magic resistance and voltaic resistance. Magnetronic Plate Armor and the Ulmish items can help.

If you do fight him in melee (using swashbuckling hopefully), a Spear of Holy Sacrifice or Moravician Bushdagger will deal heavy damage.

Steam drill bombs massively debuff blasting resistance while dealing blasting damage, which is immensely effective (and can be followed up with other explosives once you run out of them).

Holy Hand Grenades can deal a lot of damage, but Dredmor has great magic resistance, so you need Haywire Chance to use them really effectively.

Same goes for the Pearlescent Wand and Gelatinous Wand, though they're not as spectacular.

There's one ability that can cheese the entire Dredmor fight. Hover ahead to read at your own risk.

Viking Wizardry's Unholy Warcry. This can stunlock him.