When monsters are generated, is Monster Level affected by current XL or max XL acheived

nethack

My character is currently at XL17 (max so far), and I'm letting a wraith drain me prior to buying protection. I've completed my Quest, so no longer need to be at any particular level. Knowing that XL affects ML, I'm wondering if there's any benefit from lowering my level permanently, or if the previously achieved level dictates? Also, will DL eventually over-rule all of this? I'm wondering this because I haven't foud a genocide scroll and have terrible luck with the nasties.

Best Answer

From the source code (makemon.c):

zlevel = level_difficulty();
/* determine the level of the weakest monster to make. */
minmlev = zlevel / 6;
/* determine the level of the strongest monster to make. */
maxmlev = (zlevel + u.ulevel) / 2;

In plain English, monsters are generated with a difficulty between one-sixth the "zlevel", and the average of the "zlevel" and your current experience level.

"Zlevel" is a bit difficult to define. It's essentially:

  1. If you're in the elemental planes, it's the full depth of the main dungeon plus Gehennom, plus one-half your current experience level.
  2. If you've got the amulet, it's the depth of the deepest dungeon level you've reached.
  3. If you're in a branch of the dungeon that grows upwards, it's the depth of the branch entrance, plus the number of levels you've gone in the branch.
  4. Otherwise, it's the depth of the current level.

Yes, reducing your experience level will make the monsters easier. However, it doesn't make them much easier: the minimum monster difficulty is unaffected, and past dungeon level 30 (the shallow part of Gehennom), depth is the dominant factor even for someone who's been power-leveling.

In the endgame, it would seem like keeping your experience level low would be a good idea: since your experience is factored in twice, the formulas give a difficulty range of 11 to 49 for a level 30 player, versus 8 to 26 for a level 1 player. However, apart from arch-liches (29) and archons (26), the most difficult randomly-generated monsters in the game are level 22.