AC is important. It BT it functions to both reduce the enemies’ hit chance and increase your hit chance (+hitroll). In the MSDOS version, AC ranges from +10 (worst – everything hits you, and you struggle to hit everything) to -10/LO (best – you hit everything, and most things struggle to hit you).
In theory, equipment and dex bonuses should drive AC to the -20 range, but testing suggests that the MSDOS version maxes at -10/LO. The test I used to confirm this was to hex edit a character to have max stats (99), level 250ish, and 8 Spectre Snares for a total of what should be like at least -68 AC (-8 per Spectre Snare and -4 from 18 dex plus whatever bonus the added 81 dex gives). A second character was edited to have just enough EQ to get -10 AC. They independently fought the berserkers on Harkyn 3 and both got hit at the same frequency.
Of note, there are some possible edge cases. There may be a default hit chance that ignores all AC values. Along the same lines, it’s possible that high level creatures like Demon Lords might struggle to hit -20 AC in the same way berserkers struggle to hit -10 AC.
Casual experiments also suggest that aside from dex bonuses, character level does not affect hit chance. A level 1 Paladin with 0 AC has the same hit chance to hit an arbitrary monster as a lvl 255 Paladin with 0 AC.
Some important aspects of -AC for speed runs:
- The standard basic set of EQ from Garths will lower a Lvl 1 Hunter/Paladin to roughly 2 or so AC. This is enough to consistently hit Ogrelords, Samurai, and Stone Giants (but not stone golems) from level 1.
- Most of the creatures on Mangar 4/5 can hit -10AC with a relatively high frequency. Most of the highest level creatures (greater demons, storm giants, etc.) can hit -10AC with relative ease.
- I’ve not seen player characters with -10AC ever miss anything anytime ever. But I suspect that they could if enemy casters used the right spells. I’ve seen -8AC player characters start getting hit by everything due to enemy sorcerer spells.
- Demonlords/Vampirelords/Mangar can miss -10AC, the exact chance is unclear but maybe around 30%.
- Ghouls start missing around -6 or -7AC. Wraiths start missing a few points earlier. Be careful to have the proper AC before farming CAT 3.
- -10/LO AC, 200+ hp on all 3 melee, lvl 9 sorcerer, and at least one other conjurer/magician with SHSP/DRBR (preferably REST also but not required if 200+hp on frontline) is the minimum to (mostly) safely farm Berserkers.
Some related references that were educational for me on this point and that are mostly reliable, except that Fandom on occasion conflates different versions (Amiga, MSDOS) and different titles (I vs II vs III, etc.), and BardsTaleOnline’s item list has some subtle differences in the MSDOS version: