Crapknocker

I can’t give too much advice on the endgame, having only gotten there a handful of times myself, but in general, be a coward. Detect everything as thoroughly as you can before ever entering a room. Kill every weak enemy you can for exp and use every cheesy strategy you can come up with. Dig holes in walls to draw out powerful monsters and fight them one on one. If you’re an archer, use scrolls of phase door to bounce around once a monster gets into melee range with you. Use every advantage at your disposal, because once you’re in Angband facing down monsters that breathe multiple elements simultaneously, can stop time, and summon enemies that then summon more enemies, you’ll wish you had practiced running away earlier.

In general, keep more items in your inventory than you think you'll need. When you have more than 300 HP, start carrying around potions of Healing for emergencies. Speaking of Healing and Healing potions, you'll want to hoard all you can of these to prepare for the final fight. Use them if you need to, it's stupid to die with an inventory full of healing potions, but keep as many as you can for later.

Check out the Angband ladder for FrogComPosBand https://angband.live/ladder/ladder-browse.php?v=FrogComposband&r=&c=&n=&e=&s=0, especially other characters of your class. Read spoilers on monster levels, spells, anything you can find.

Advice for quests found in towns: https://pastebin.com/ZLZZz45j

Demigod mutations: https://pastebin.com/hTi24Nky

Arena rewards and various other small spoilers: http://nikheizen.github.io/pages/rewards.html

Dungeons, dungeon guardians and quests: https://pastebin.com/AVsp31k8

One last bit of advice, maybe try the Munchkin personality if you get stuck in a rut. It gives huge boosts to your stats, makes it easier to level up, and starts you with a million gold. You can't really get credit for beating the game using this mode, but it is great for trying new character combos and learning how places you've never been work. It's worth checking out at least once, especially if you're learning the game. Preparing to fight big J

Some tips I've gleaned from excessively reading winning posts on the Angband ladder on what to do and how to prepare to fight the Serpent of Chaos:

Double breaths

You have to have a bunch of HP to even think of fighting the serpent. The main reason for this is that the big guy is super fast and even at +35 speed can get two moves on you before you have a chance to react. If the serpent decides to breathe some exotic element on you like chaos, it’s a problem. If he decided to do it twice in a row, it can be deadly. Having a big batch of HP is the best way to deal with this. That way, if you get taken down to minimal HP you can teleport out to heal before resuming the fight.

Another thing to keep in mind is that these double moves can occur halfway through the fight or when you’ve got him down to his last bit of health. You will need to keep your HP above a certain level to avoid instant death if the serpent gets a double move on you. The energy system underlying the turns in the game is somewhat randomized, so you won’t know this is coming until you get hit with it. Keeping your HP up is the best defense alongside having your resistances covered.

To help buoy your HP levels, you can do a bit of manipulation with your Life Rating. If you managed to come across a potion of Self Knowledge, you probably noticed you had something called a life rating. Here’s how I understand this system to work. Every level up, the game rolls some dice behind the scenes to determine how much HP you gain. Over the 50 levels you have available, a series of bad rolls can really hamper your total HP. To counteract this, you can drink potions of New Life, which reroll these dice and can give you a larger HP pool and potentially different stat maximums. Your life rating is a general feel of how high you could’ve gotten on these HP rolls. Anything over 100% is great here and potentially worth keeping. Basically if you stockpile enough potions, you can drink a New Life followed by a Self Knowledge to see how good your new life rating is. This can get you 50 or more HP in the endgame, which is nothing to sneeze at and may save your life.

Summon uniques

The Serpent of Chaos has a power that I think no other boss in the game has, to summon unique monsters. If you have gotten to him (it?), you have probably gotten surrounded by bunches of high level undead summons, dragon summons and tons of others. But summoning unique monsters is probably the most nasty one of them all. As you probably already know, unique monsters are some of the hardest to defeat in the game and can complicate any encounter they pop up in. This goes double if the encounter is with the toughest boss in the game, the Serpent of Chaos.

The quirk here is that the serpent will only summon uniques that are currently living, i.e. those that you haven’t defeated yet. The problem here is that there are a bunch of high-level uniques that can make your life hell in the lower depths of Angband. Some especially nasty ones are Godzilla and Nodens, both of which have boatloads of HP and devastating attacks so you don’t want to be engaging with them at the same time as the serpent.

One approach is to troll the lower levels of Angband in the 90+ range and try to kill all the uniques that pop up there. This is useful for two reasons, one it lowers the amount of uniques that the serpent can summon and two it gives you the really useful drops of the uniques from that low in the dungeon. Better equipment is always better.

Another way to deal with unwanted summoned uniques is to use scrolls or staffs of Destruction, which turn the usual dungeon terrain into random mashes of stone. Uniques caught in the radius of a destruction spell will be despawned from a level (not killed). However, if you accidentally catch the serpent in the radius of your destruction spell, he will also be despawned. But then he will immediately be respawned elsewhere in the level at full health, so you really don’t want to do this unless you’re trying to escape or something.

But destructing the level before the serpent finds you can be a useful strategy to limit line of sight and the summons that might occur. Enemies can only be summoned in the squares surrounding your @ character. If your back is to a wall, that’s a few less squares that bad guys can occupy trying to kill you. The only downside to this is that the serpent immediately knows where you are on the level as soon as you go down to 100 and will begin making his way toward you, smashing down any walls between you and him as he goes. Even if he tunnels through a few walls, taking control of the terrain you fight on can give you an edge in this battle of attrition.

There are a few things you can do to help even the odds, though. The first, if you’re planning on fighting the serpent in melee is to have as much damage as you can without sacrificing too much in the way of resists. Having a few pluses to hit and damage on random bits of equipment can end up giving you hundreds of extra damage per round. You’ll want at least 500 damage per round to even stand a chance in melee, and the more the better.

A few notes about the Serpent of Chaos. First is that he’s not immune to stun, so if you have a weapon that stuns or a reliable stunning attack, you can make the fight much easier by keeping him stunned, which I believe increases his chance to fail casting any magic (including summons) and lowers his chance to hit you in melee. Second, he’s considered an evil, living monster so if you use gloves of slaying that do extra damage against either evil or living monsters, they will work on him as well. My third note is that he frequently breathes chaos, so bring along at least double chaos resist to help mitigate that damage. He also has an aura of shards, so don’t go up against him without resisting that.

There are a few other techniques to reduce or prevent the serpent’s summoning powers. If you can mix it into your equipment, there are amulets of anti-summoning that exist in the game (denoted by [Sm). Keep your eyes out for those. Some classes have access to anti-magic, which also helps prevent summoning, which is also available in amulet form ([M). You can also turn the tables and have your own summoned minions occupy all the spaces around you so that big J’s summoning is blocked that way. This can be doubly helpful if you bring heavy monsters of your own to fight on your behalf. Some classes can summon dragons and Great Wyrms of Power (GWOPs) and Steam-Powered Mechanical Dragons are two types that I’ve heard hold up decently against the serpent. Even non-summoning classes can get in on the act by capturing these monsters in the capture balls available in certain stores, then throwing them (‘v’) when you want to release them, Pokémon-style. But be aware, the chaos breath he breathes has a tendency to polymorph monsters occasionally, so your big badass summons might get turned into tiny, fragile rats.