OK, you have the Mystaran kraken listed as "working," but I think you can remove the [?] from the language line and call it done. I like that choice.
Want to do the Birthright ones next?
The Brecht priests' claim it's extraplanar in original seems unlikely on the face of it, although I suppose it could be a Fiendish/Half-Fiend/Water-Element Kraken that used to live in the Abyss or the Elemental Plane of Water. That could give it the SR of this monster, but might add more SLAs the original text makes no mention of!
I can go for Native Outsider as you suggest. And it had better be Colossal!
(Heh heh, I have a strange fondness for Colossal+ if you feel inclined to make it really big.)
The average 2E kraken has 90 hp, so this has 2-4/9 times as many hp. The 3E kraken gets 110 hp on average from its HD. If we just use the 2-4/9 multiplier in an approximate way, that should give this thing almost 60d8 for HD (270 hp average). That seems like quite a lot! On the other hand, 30d8 is only 135 hp on average, which seems low. Split the difference at 40 to 50 d8 and just make sure it's got plenty of Con?
I would be willing to consider making it extra large on the Colossal scale.
Well, we could always make it Colossal but at the large end of that range. How does that work for you?
I'd be ok with 40 HD (splitting the difference of your estimates) and giving it a good Con score. Does that sound good?
Since we'd opted for Colossal+ I'll put in 40 ft./30 ft. as a placeholder.So what Space/Reach shall we use then?
I'm happy with your suggested ability scores.
I also like 50 ft./40 ft. (90 ft. with tentacle, 60 ft. with arm). Nice and big! And it fits the picture well enough.
Standard Imp Grab and Constrict with the shorter arms? Maybe Imp Grab and some kind of ship damaging attack for the tentacles.
The picture doesn't have a beak, but the original text does. We'll have to choose.
Shall we just give it the Mystaran Kraken's Shipcrusher special ability?