That'll work for me!
How about making the next feat Power Attack?
CR 5 looks ok. By eyeball, they're probably roughly on par with the Medium Adult Tojanida.
How about making the next feat Power Attack?
CR 5 looks ok. By eyeball, they're probably roughly on par with the Medium Adult Tojanida.
I reverse-engineered it two size steps (–2) and 10 Hit Dice (–3) down from the Adult's CR 11 and then knocked off another –1 CR since it's special attacks are less effective.
To me it eyeballs more like a CR 4.
Just compare it to, say, a CR 4 Rhinoceros (which is notably tougher!) or CR 5 Troll (more hp, higher damage, plus regeneration).
The Tojanida has similar hp, but considerably harder Armour Class (AC 23 vs AC 16) and does twice as much damage (2d8+3+2d6+2 vs 1d8+6 or 2d4+6 averages 21 vs 10.5/11).
That suggest the adult might be a CR 10 rather than 11, with the young CR 4 (I'd keep the Huge adolescent at CR 7).
The Advanced Young Afanc looks good.
That feat selection works for me too!
CR 10 and 4 is also fine. As you say, CR is definitely an art, not a science.
Shall we crib from the adult for the young tactics?
Like adults, young afanc often wait for prey to come looking for them and attack smaller ships (up to 40 feet) with the youthful whirlpool attack. They usually avoid larger vessels. Some young afanc develop other tactics, also like adults.
If it can attack opponents in the water, it will in preference to attacking a vessel. An afanc prefers to bite and swallow prey but will use its flippers if hard pressed.
Did we discuss making the "whale disguise" an actual ability?
Young afanc live in freshwater, usually major rivers or large lakes. Like adult afanc they can breathe air as well as water, so can survive in waters too foul or unoxygenated for a normal fish to breathe if they can find enough to eat. Afanc are much more social when young and usually swim in the company of other afanc of the same age, usually siblings from the same clutch of eggs. They are reluctant to associate with afancs a lot bigger than themselves, especially unrelated ones, since larger afancs might decide they'd make better meals than hunting companions. Afanc are far more independent than wolves and a group of young afance does not have a "command hierarchy" as such, but still cooperates efficiently to hunt prey and fight off enemies or rivals.
CR 7 for the Huge ones seems ok. And I agree with making the alignments match!
Flavor and tactics look great!
A +5 racial bonus to Disguise seems appropriate. Actually, where does it say in the original that the young look like carp? I'm not finding it. Anyway, should the Disguise bonus just apply to the adult? Let's figure that out, then I think these are done.
Oh, also, we should use the name gawwar samakat somewhere!
I like your minor edits.
I'm ok with describing the young as looking like carp, but I just think giving them a Disguise bonus as carp as straying a little too far from the original. Besides, they're a bit too large to be carp.
The Zakhara blurb looks good!
Young Afanc Working Draft
A huge fish that resembles an enormous carp several times longer than a human is tall, dull gray in color and covered in heavy scales. Its forefins are longer and more flexible than a carp's.
+SNIP+
A typical young afanc is around 12 to 15 feet long and weighs 800 to 2,000 pounds. Afanc smaller than that don't attack people and are hard to distinguish from dull-coloured carp. A newly hatched afanc is about a foot long and a pound in weight.
Combat
Young afanc hunt in packs. They will use organized tactics such as flanking attacks or having one of their number pretend to be an "injured giant carp" to lure fishermen or other predators into an ambush. Young afanc can cooperatively create whirlpools and often use this ability to sink small watercraft in order to attack the occupants. Older adolescent afanc can also ram vessels in a bid to capsize them, they rarely use this attack on anything larger than a keelboat.
Updating the Afanc Working Draft.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.