Bosses

Diablo 2 gates each act behind one named demon, so the five act bosses arrive in a fixed order and get harder as you go. That much is obvious from playing. What is less obvious, and only shows up when you put our five boss pages side by side, is that the two you are supposed to kill over and over are not the two that pay best. They are the two that die fastest.

So this guide sorts them by price rather than by act. First what each kill costs you in health you have to chew through, then what it pays back, then the single resistance number that decides how the fight actually goes.

The ladder, on Hell

Health and experience both climb in step with the act, which is what you would expect. Two things break the pattern. Duriel is listed a level above Mephisto despite dying an act earlier, so the Act 2 boss is technically the higher-level monster even though he has ten thousand less health. And Diablo and Baal carry byte-for-byte identical figures on our pages at every difficulty, right down to the 2,195,808 experience. Whether that is a real quirk or one page copied from the other, we have not been able to settle from our own material, so it is flagged rather than explained away.

The gap between the ends of that ladder is the number to hold onto. Baal is worth almost four times as much experience as Andariel per kill, but he also has nearly twice the health, sits at the end of a full act, and makes you fight through five waves of minions before he will even engage. Andariel is a straight walk down four floors of Catacombs.

Which is why the farming guides are for the cheap ones

Two of the five have a dedicated farming page in this bucket, and they are the first and third rungs of that ladder, not the top two. That is the whole argument for boss running in one sentence: a boss you can kill three times in the time it takes to kill Baal once is worth more than Baal, whatever the experience column says.

Andariel farming is the cheapest loop in the game and the page is honest that her loot table is thin, calling her a boss nobody chases for items. What it is really selling is speed and the Quest Drop Glitch, which involves killing her for the first time, town-portalling back, talking to Warriv and heading east without leaving the game. The awkward part is not the fight, it is the Catacombs. The trick the page gives is that the maze is consistent: if you are heading right, every left corridor dead-ends, and if you are heading left, every right corridor walls up. From the Catacombs Level 2 waypoint you can teleport most of the way there.

Mephisto farming is the one people actually run, because he pairs a weak fight with the best loot table of the three lesser evils. He is at the top left of Durance of Hate Level 3, reached from the Level 2 waypoint by hugging the wall clockwise. The method is the moat at the centre of his room: lure him to one side, teleport or run to the other, and his pathing gives up. He can see you and cannot reach you, and a ranged character kills him from there in two or three minutes. Watch for the Stygian Dolls on the way in, which explode when killed.

The same room pays out twice more if you are already there. The Council Members at the entrance drop well if your character can handle them, there is a super chest in the top left corner with a shot at rare items and high runes, and the two racks flanking Mephisto himself are worth breaking.

The number that decides each fight

Every boss page carries a resistance table, and in almost every case the sensible reading is that you want the element the boss resists least. One boss breaks that rule in your favour.

Andariel is the only boss on any of our pages with a negative number in that column, and it does not move: her fire resistance is -50 on Normal, Nightmare and Hell alike. She takes extra damage from fire for the entire game. Nothing else in this bucket hands you a weakness that never closes, and it is a large part of why the first act boss stays farmable at level 75.

Duriel is the reverse case. His cold resistance climbs from 50 on Normal to 75 on Nightmare to 95 on Hell, the highest single figure on any of our boss pages, which is awkward because the standard answer to a boss that charges you is to slow it with cold. He also fights in a small chamber and carries a Holy Freeze aura that slows you instead. Our page recommends dragging him into the larger room and keeping a summon between you and him while you portal out if it goes wrong.

Baal is the only one where the resistance table is not really the point. He has eight named spells including a clone of himself, and before any of that you have to clear five waves led by Colenzo the Annihilator, Achmel the Cursed, Bartuc the Bloody, Ventar the Unholy and Lister the Tormentor. Budget for the waves, not the boss.

The one thing all five owe you

Once you have spent your free respecs, a Token of Absolution is your only remaining route back, and the four essences it needs come from these five bosses on Hell difficulty and nowhere else. Andariel or Duriel drop the Twisted Essence of Suffering, Mephisto the Charged Essence of Hatred, Diablo the Burning Essence of Terror, and Baal the Festering Essence of Destruction. Combine all four in the Horadric Cube and you can reset your skills and stats as often as you can farm them.

That is the quiet reason these five stay relevant after the story is done. The act bosses stop being obstacles and become the only renewable source of the one thing in Diablo 2 you otherwise cannot buy back: a second chance at your build. If you want the areas rather than the monsters, our best farming areas guide covers the zones these runs pass through.