*Here's a little article I wrote while trying to expand my own understanding of the game. I decided to share it with you, because I thought some of the things I discovered might be useful to other people like me, people who are no D&D or modding veterans, but no complete newbies to Baldur's Gate II either.*

I apologize in advance for any mistakes/typos/miscalculations included within this article (there's bound to be some), and will do my best to correct these flaws when they are pointed out to me.

Regards,

Revi

I apologize in advance for any mistakes/typos/miscalculations included within this article (there's bound to be some), and will do my best to correct these flaws when they are pointed out to me.

Regards,

Revi

**THAC0 'Soft Cap': Overview of Lowest AC's in SoA and ToB**

The following formula determines to-hit rolls in Baldur's Gate II:

THAC0 - (roll on a d20) = AC hit

There is, to my knowledge, no hard-capped lowest THAC0, but if we know the AC's of the most powerful enemies in the game, we should be able to calculate at what point decreasing your THAC0 any further stops increasing your chance to hit enemies.

Using Near Infinity, I was able to figure out the AC's of most of the powerful enemies in SoA and ToB.

SoA

Greater Werewolf: -6

Lesser Dragons: -10

Greater Dragons: -12

Bodhi: -1

Irenicus: 0

ToB

Lesser Demons: -5

(Fallen) Solar: -5

(Fallen) Planetar: -7

Greater Demons: -8

Lesser Dragons: -10

Greater Dragons: -12

Abazigal: -12

Demogorgon: -12

Gromnir: -5

Melissan: -8

Sendai: -3

Yaga Shura: -8

This gives us some real data to plug into the formula. -12 AC appears to be a significant landmark, since it's used for some of the hardest in game enemies.

Now we have to define what we mean when we say we want to maximize a character's chance to hit his enemy.

For every attack a character makes, the system rolls a d20 and subtracts this number from the character's THAC0, as per the formula mentioned previously:

THAC0 - (roll on a d20) = AC hit

We now have a number to plug into this formula instead of 'AC hit':

THAC0 - (roll on a d20) = -12

Next, we need to determine the lowest possible roll on a d20. The lowest possible roll on a d20 is obviously 1, but 1 counts as a critical miss, no matter the circumstance. This means there's a hard-coded 5% chance to miss, regardless of how low your THAC0 goes. It also means 2 is the lowest possible roll that can still count as a hit.

Let's plug that number into the formula:

THAC0 - 2 = -12

With these numbers filled in, it becomes obvious what the THAC0 in this formula is:

-10 - 2 = -12

In other words, in order to be able to hit every enemy in the game 95% of the time, you need a THAC0 of -10. And a THAC0 that is any lower than -10 will not increase your chance to hit any further.

The implications of this at high levels could be far-reaching. A THAC0 of -10 is easily achieved by any fighter character above level 20, without ever specializing up to Grand Mastery in a weapon.

Knowing exactly where the soft hit cap lies will certainly influence me in the choices I make in the distribution of THAC0-boosting items and specialization points on my next run through.

This especially affects fighters, rangers, and paladins, whose natural THAC0 drops down to 0 at level 21. When you consider the fact most of your these characters will end up wielding +5 weapons or better during the final fights of ToB, you could consider half of that -10 THAC0 already taken care of. This leaves -5 THAC0 to come from gear and specialization.

To demonstrate how easily this can be achieved, let's take a character with a 2 point specialization in scimitars, wielding Gram +5, with a natural THAC0 of 0:

THAC0

Natural THAC0 0

2 point specialization -1

Belt of Hill Giant Strength -3

Gauntlets of Weapon skill -1

Gram -5

Total -10

So from a THAC0 point of view, placing more than 2 points in any weapon specialization is a waste, unless of course you do not intend to wear any THAC0 enhancing gear. Note that the example I've provided here is already quite extreme; it is unlikely a character that has access to +5 weapons would still be wearing a belt from the Adventure Mart or gloves from the Planar Prison. By the end of the game most melee characters would have access to better Strength and THAC0 enhancing gear.

This also puts the ranger and paladin classes in a new light. I used to consider both of these classes 'wannabe-fighters,' because I knew they could never specialize beyond 2 points in any weapon. I still played these classes because I enjoyed them from a role playing perspective, but was always irritated by their 'weakness' compared to the vanilla fighter.

As my example shows, this opinion was misinformed. With some gear, a decent weapon, and 2 points of weapon specialization, any melee character above level 21 can hit anything in the game just as well as a pure fighter in top-notch gear wielding sporting grand mastery in two-handed swords. The game is quite forgiving in that sense.