I answered this in the Oriental Adventures thread, but it would make sense to have any discussion of the issue here since we're in the middle of a Conversion on that thread.
Looking at the current 3.5 conversion of the Krakentua I notice a couple of out-and-out errors apart from the questionable Armour Class issue.
The female krakentua has saving throws of Fort +32, Ref +20, Will +34.
However it's a 50 HD Aberration with Dex 11, Con 32, Wis 25 and the Lightning Reflexes and Epic Reflexes feats, so those should be:
Fortitude (weak) = +16 from HD, +11 from Con 32 =>
Fort +27
Reflex (weak) = +16 from HD, +0 from Dex 11, +6 feats =>
Ref +22
Will (strong) = +27 from HD, +7 from Wis 25 =>
Fort +34
So two of its saves are wrong! The male's saves are also in error:
Fortitude (weak) = +16 from HD, +9 from Con 28 =>
Fort +25
Reflex (weak) = +16 from HD, +0 from Dex 11, +6 feats =>
Ref +22
Will (strong) = +27 from HD, +8 from Wis 27 =>
Fort +35
By the way, I have no idea why we gave the Male Krakentua 2 points more Wisdom than the female. It has no precedent in the AD&D sources as far as I can tell.
There is a second problem. The krakentua has Multiweapon Fighting as a normal feat, but
Multiweapon Fighting has a prerequisite of "Dex 13, three or more hands" and the Krakentua's Dexterity is only 11. Oops!
We could fix that error by making Multiweapon Fighting a bonus feat and giving it yet another normal feat - I'd favour Improved Multiattack so it can punch without penalty.
Speaking of punching, I'm not enamoured of the slam attacks only doing 2d6 damage. The original OA2 Krakentua could punch for 4-40 damage, so I was thinking 6d8 or 8d8 would be a more appropriate slam damage.
Oh, and it still feels a bit underpowered for Challenge Rating 30. It reads more like a mid-20s CR, maybe even low-20s due to its pathetic AC and poor defenses.
How well would one fare in a fight against, say, CR20 Balors or CR23 Solars? If it really is CR30 it should steamroll several balors.
Let's see, a balor making an 11-point Power Attack has a 50% change of hitting the krakentua's AC 16 with the weakest iteration attack from its
+1 vorpal longsword's +31/+26/+21/+16 melee. (+6–11 is +5 melee, so an 11+ roll is needed to hit 16+).
Of that 50%, 10% are potential criticals of which 5% are potential vorpal criticals, so:
45% normal hits (average damage 11)[
2d6+13 +11 power attack –20 krak's DR]
2.5% normal critical hit (average damage 42)[
4d6+26 +22 –20]
2.5% vorpal critical hit [
average damage death by decapitation!]
The +21 melee attack has a 75% of hitting, so:
67.5% normal hits (average damage 11)[
2d6+13 +11 power attack –20 krak's DR]
3.75% normal critical hit (average damage 42)[
4d6+26 +22 –20]
3.75% vorpal critical hit [
average damage death by decapitation!]
And the +26 and +31 melee attacks have a 95% chance (due to the miss-on-1 rule):
85.5% normal hits (average damage 11)[
2d6+13 +11 power attack –20 krak's DR]
4.75% normal critical hit (average damage 42)[
4d6+26 +22 –20]
4.75% vorpal critical hit [
average damage death by decapitation!]
The +25 and +30 attacks of its
+1 flaming whip also have a 95% chance:
90.25% normal hits (average damage 3)[
1d4+6+1d6 fire +11 –20]
4.75% normal critical hit (average damage 26)[
2d4+12+2d6 fire +22 –20]
So if my sums are right, a single full attack from a Balor (with 11-points of Power Attack) will do an average damage of 43.9525 hit points [
2.835×11 + 0.1575×42 + 1.805×3 + 0.095×26 = 36.0675 + 7.885] to a Male Krakentua plus a 14.8596712890625% chance of vorpal death [
100% minus the odds of all its attack failing to vorpal, which is a hundred times 1–(0.975×0.9625×0.9525×0.9525) = 1–0.851403287109375 = 0.148596712890625].
So there's almost a 15% chance of it just autoslaying the krakentua.
A male krakentua can 95% hit a Balor's AC 35 with its +43 melee wakizashas. However, it cannot use Power Attack because wakizashas are light weapons.
So for the primary wakizasha that's:
85.5% normal hits (average damage 14)[
4d6+15 –15 balor's DR]
9.5% critical hit (average damage 43)[
8d6+30 –15]
Hold on, there's an error here. Shouldn't the primary wakizasha be an iterative attack rather than a single one? So the Full Attack line ought to go "or wakizashi +43/+38/+33/+28 melee (4d6+15/19-20) and 6 wakizashis +43 melee (4d6+7/19-20) and 2 slams +42 melee (2d6+7)"?
Never mind for now, I prefer it a single attack anyway!
The six secondary wakizasha's are:
85.5% normal hits (average damage 6*)[
4d6+7 –15 balor's DR]
9.5% critical hit (average damage 37)[
8d6+14 –15]
*the actual average damage is slightly higher than 6 since I didn't adjust for negative results being 0 damage (i.e. a roll of 7 or less on the 4d6–8 damage).
It'd definitely be better off using its tentacles with a 12-point Power Attack, which is just enough for a 95% hit chance.
90.25% normal hits (average damage 19)[
2d6+15 +12 –15 balor's DR]
4.75% critical hit (average damage 53)[
4d6+30 +24 –15]
The two slams need a 5+ to hit with that Power Attack, for an 80% hit chance:
76% normal hits (average damage 11)[
2d6+7 +12 –15]
4% critical hit (average damage 37)[
4d6+14 +24 –15]
So a single full attack from a Krakentua Male (with 12-points of Power Attack) will do an average damage of 157.335 hit points [
7×(0.9025×19 + 0.0475×53) plus 2×(0.76×14 + 0.04×37) = 7×(17.1475 + 2.5175) plus 2×(8.36 + 1.48) = 7×(19.665) + 2×(9.84) = 137.655 + 19.68] to a Balor, so would need around two rounds to bring a Balor down to negative hit points from its 290 hit point maximum.
By contrast, a balor making two full attacks with 11-point power attacks will do around 88 hit points of damage to a krakentua but has a roughly 27.5% chance of Vorpalling it to death [
1 minus the square of 0.851403287109375].
Indeed, a full-attacking balor would be better off reducing the Power Attack to 2 points to maximize its chance of critting with its vorpal longsword to 4.75% for all eight of the attacks - giving it about a 32.25% chance of vorpal decapitation [
1 minus 0.9525 to the eighth power, or 1–0.67751649758197765844879150390625].
However, the Balor would be FAR better off using its flight and
greater teleport powers to make hit-and-run attacks. It'd be way better off exchanging standard attacks with the krakentua than staying in one place long enough to receive a full attack.
Wielding its longsword two-handed for an extra 50% strength bonus and applying 19 points of Power Attack so its +33 melee has a 95% chance of hitting the krakentua's AC 16:
85.5% normal hits (average damage 21)[
2d6+25 +19 power attack –20 krak's DR]
4.75% normal critical hit (average damage 82)[
4d6+50 +38 –20]
4.75% vorpal critical hit [
average damage death by decapitation!]
That's an average of 21.85 damage [
0.855×21 + 0.0475×82 = 17.955+3.895] with a 4.75% change of Mr Squidhead becoming Mr Squidheadless.
By contrast, the best the krakentua can do is a single Power Attacking tentacle slap for 19.665 average damage.
At that rate, it'd take a krakentua fifteen rounds to slap a balor to death, during which time it'll be slashed down to roughly half its 675 hit points of damage (average damage from fifteen power-attacking 2H longsword blows by the Balor being ~327). However, fifteen attacks have a 51.8% chance of vorpal fatality.
That means that TWO balors would be almost certain to kill a male krakentua from damage or decapitation.
A Solar however would simply slaughter a krakentua, if only because it has regeneration that a standard krakentua has no way to overcome, so even if it does manage to bring its angelic opponent down to minus 10 hit points the Solar would simply get up again (plus it has 3/day
heal). That's unlikely to happen since a Solar will just fly out of tentacle reach and rain down
arrows of slaying until the krakentua is dead. Aalthough the DC 20
slaying effect is useless against the Fort +32 male krakentua and the arrows will only do 14 average damage a hit (or 42 on a critical), a krakentua has no way to shoot back.
Yes, that's definitely looking more like a CR 22 to 24 than a CR 30 to me. Not that Epic Level Challenge Ratings are an exact science.
Might compare it to a few weak Epic Level Handbook Monsters and see how it rates, not that they are at all balanced!
Lets see, the
Elder Treant has the same Hit Dice as a Krakentua and is significantly tougher in some of its stats (1,145 hp, AC 41, +51 melee) but is only CR 25.
EDIT: oh and the Treant's +51 melee slam can 95% hit the krakentua even if its Power Attack is maxed out to 37 points!
85.5% normal hits (average damage 71)[
10d6+19 +37 –20 krak's DR]
9.5% critical hit (average damage 167.5)[
21d6+38 +76 –20]
That's an average of 76.6175 damage [
0.855×71 + 0.095×167.5 = 60.705+15.9125], or 153.235 it it full-attacks with both slams.
The best Power Attack against an Elder Treant a Krakentua can do is 4 points with its Tentacle slaps:
90.25% normal hits (average damage 16)[2d6+15 +4 –10 treant's DR]
4.75% critical hit (average damage 42)[4d6+30 +8 –10]
The two slams need a 5+ to hit with that Power Attack, for an 80% hit chance:
76% normal hits (average damage 3*)[2d6+7 +4 –15]
4% critical hit (average damage 26)[4d6+14 +8 –15]
*the actual average damage is slightly higher than 6 since I didn't adjust for negative results being 0 damage (i.e. a roll of 7 or less on the 4d6–8 damage).
So that's an average of 16.435 for a single slap [
0.9025×16 + 0.0475×42 = 14.44+1.995] or 121.685 for a full attack [
7×(16.435) plus 2×(0.76×3 + 0.04×26) = 115.045 + 2×(2.28+1.04) = 115.045 + 2×(3.32) = 115.045+6.64].
