In spite being named after the boy-turned-fish-and-back, none of the Sundue family members in The Gerosha Chronicles are 100% faithful to the myth from which they derive their codename. The original myth can be watched here.
It's definitely not Isitoq
Given that he's always been melancholy, serious, and an introverted sigma male of sorts, Isitoq Sundue from Anarteq: Guardian of the Soo is probably the least faithful to the source material! Also, while willing to hunt and fish when living alone, Izzy's career as Anarteq oddly enough has little to do with hunting caribou, and plenty to do with sabotaging Icy Finger equipment and vehicles / vessels, as well as other random superhero-type activity.
Izzy derives much of this from the fact that the Mahaha operatives robbed him of the innocence of his youth early on. He was never able to gain much footing with regard to developing a strong social circle in school either, encouraging him to be a lone wolf - or get involved in Order-related activities. Outside of his own father Toklo, and uncle Tulimak, there were few with whom Izzy felt he could truly connect. He got along fairly well with his mother, Anjij; as well as with his aunt Siaja, with his cousin Jissika, and with the Order's relic keeper and storyteller: Nanaouk Kunuk.
At that point, however, Nanaouk had basically become family to Izzy. Sure, he was able to make friends with Emeraldon over time; but they had similar personalities. Even Izzy is surprised how well he meshed in the end with Moira "Li'Ban" Flanagan, not initially expecting that they'd get anywhere.
Waiting too long to make a move, and being too methodical, have been some of his biggest character flaws. It was his stubbornness at not wanting to go with Jissika, not form a plan on the fly when the situation called for it, want to deliberate an extra day or two with her before doing anything, etc.; that led to Jissika lashing out and doing the extreme opposite foolish thing - which left her at the mercy of Wishpon, and later at the mercy of SCALLOP and the Kirby Act.
The original Anarteq's folly was being too playful and reckless when hunting. Therefore, while Izzy has a merman form and can relate to the original myth that way; he otherwise has very little else in common with the source material.
It's not Jissika either
Jissika Sundue, as Nemara, is possibly an inversion of gender roles in the original myth. While she probably wouldn't be a jokester while hunting caribou, she is very extroverted and...flirty, in many social situations. The original Anarteq's sisters had higher morals, and were not quite so outgoing and reckless.
It's not Toklo
While not the magnitude of stick-in-the-mud that Izzy can be, his father Toklo was also pretty serious from early on. But unlike Izzy, who would jeopardize the mission by wanting to secure his solitude; Toklo was willing to sacrifice what he wanted much more readily for the good of others. His determination to rid the north of Icy Finger operatives like Mahaha, however, proved to be his downfall. And his being killed by one of them was partially what drove Izzy to become as introverted as he did.
At any rate, Izzy wasn't quite as reclusive before Toklo's death.
So who?
The best case of who might count as being a somewhat accurate Anarteq would either be Izzy's grandfather, Akiak Sundue, or else his uncle, Tulimak Sundue. However, learning he had salmon powers wasn't what drove Akiak to take his cause unto the Order seriously. He'd always somewhat done it, even if he were more outgoing, friendly, and extroverted than either Toklo or Isitoq.
What truly drove Akiak to become serious, was when he saw the Icy Finger create their own version of Inukpak to punish tribes that wouldn't pledge allegiance to the Icy Finger. How dare they appropriate the identity of Inukpak the Giant for such nefarious purposes!
Before the Mahahas, which became an obsession for Toklo and Tulimak to deal with, Inukpak was one of the great threats for Akiak to take down. His success resulted in his worth being proven to one Tobey Flippo, as one Fred Thernip. This led to him being added on to the Phexo Quartet, where he'd aid in the Japanese theater of war and would aid Donald "Arrowfrog" Walters from South America in dealing with the threat known as "Molarity."
While Akiak loved to mess around while hunting, he knew his limits. Perhaps the greatest match to the original myth, therefore, was Tulimak.
Tulimak was a screwball when hunting and fishing; though he wasn't cosmically punished for it. He took his saboteur / hero work seriously, though less so than his brother Toklo did.
Where Tulimak really fell short, and it proved his downfall, was in his behavior around women. He lacked the maturity to marry Siaja Tiktak after learning he'd impregnated her. He wasn't a very good father to Jissika either, leading to some of her teenage rebellion antics. This was made worse when he mysteriously vanished one day while Jissika was still a little girl, leading her to suspect that he was simply being a deadbeat. Izzy wanted to believe the current Mahaha or one of his Qalupalik soldiers had killed Tulimak, as they had previously done Toklo in. Jissika, however, believed that Tulimak skipped town because he didn't want to be a family man.
In spite all of this, work as an Anarteq operative was dangerous. By the time Izzy embarked on his mission to Sault Ste Marie, the previous three male Anarteqs were already either dead or missing. And instead of having to learn not to be foolish on the water, Izzy had to learn that it was risky to procrastinate too much on land. The price he paid for it? Being exiled from Canada by the Trudeau regime for saving the world; while being forced to abandon his cousin - as she remained confined inside a Michigan juvenile prison.
