It seems like the real problem is that we gave the Mystaran kraken too much AC compared to a normal SRD kraken! I think our best compromise on AC is #6!
Well the AC was bit the only aspect of the Mystaran Kraken that was a bit too much compared to the regular version! We were just aiming for something CR-appropriate.
Anyhow, let's use #6 then.
Updating
Awnshegh Kraken Working Draft.
Thoughts on the speed? It seems like they're 3x faster than a standard kraken and only a little faster with the jet. It would be something like Swim 60 ft with a jet speed of 320 ft, just using the 2E ratio.
Well AD&D Kraken have Swim 3 or the equivalent of a 10 ft. speed in 3E. The SRD Kraken's 20 ft. matches AD&D speed 6 or 9, so it's already got a speed boost to match the Awnshegh version.
Still, I reckon it ought to be faster so how about we just slap another 10 ft.?
I'd make the Jet multiplier ×6 double move rather than the SRD Kraken's ×7. It'll still end up faster and it's a better homage to the original's Jet 21 & Jet 24.
Speed: Swim 30 ft.
Jet (Ex): The Kraken can jet backward once per round as a full-round action, at a speed of 360 feet. It must move in a straight line, but does not provoke attacks of opportunity while jetting.
Looks like it's the regeneration/fast healing question next.
Since the original ability does not require special means to kill its possessor, it's not a "kill it with fire" style autohealing ability so is Fast Healing in 3E terms, but the Major Regeneration version the Kraken possesses does enable the possessor to regrow lost body parts "within weeks" (30 days minus 1 day per Constitution point).
The original stats don't give it a Constitution score or Hit Dice, just 220 hit points and saves as "Fighter 24", but I can make a couple of guesstimates…
Guesstimate 1: 220 hp and 24 HD standard monster => Hit Dice 24d8+112 => 4⅔ hit points per Hit Die => Con 19.
Guesstimate 2: 220 hp and 24th level fighter => Hit Dice 9d10+45 base plus 125½ bonus => 13.944 hit points per Hit Die. Which is way over the +7 of AD&D's maximum score of Constitution 25. The table goes from +6 at Con 21 to +7 at Con 24, so if the progression was consistent that'd be Con 45!
Guesstimate 3: 220 hp and 24th level fighter
who rolled max hp => Hit Dice 9d10+45 base (90+45) plus bonus => Hit Points 135 base plus 85 bonus => 9.444 hit points per Hit Die. Still way over Con 25, but less extreme - maybe Con 30?
Oh well, that didn't work very well!
Let's just say it had the equivalent of Con 20 or so and regrew organs in 10 days or so.
That means he'll regrow severed limbs much faster than the 1d10+10 days of an SRD Kraken.
How about:
Special Qualities: Darkvision 60 ft., fast healing 5 [
regrows body parts], jet [
360 ft.], low-light vision, spell resistance #, spell-like abilities
Combat
Tactics.
Krakens strike their opponents with their barbed tentacles, then grab and crush with their arms or drag victims into their huge jaws. An opponent can make sunder attempts against a kraken’s tentacles or arms as if they were weapons. The kraken’s tentacles have 40 hit points, and its arms have 20 hit points. If a kraken is currently grappling a target with one tentacle or arm, it usually uses another limb to make its attack of opportunity against the sunder attempt. Severing a kraken's tentacle or arm deals damage to the kraken equal to half the limb’s full normal hit points. A kraken usually withdraws from combat if it loses both tentacles or three of its arms. The kraken regrows severed limbs in 1d4+4 days.
Fast Healing (Ex): The kraken's fast healing can regrow lost portions of its body provided it can survive their removal. Unlike regeneration, it can not reattach severed body parts by holding them to the stump. Regrowing lost organs or body parts takes 5 to 15 days (2d6+3), depending on the severity of the injury; severed limbs can regrow entirely in 5 to 8 days (1d4+4).