She's Ursula's daughter who is in fact related to Triton.

Tritons are basically Sea elfs. They have traditionally be loners and secluded. Perferring to stick to their own communities or the sea in general rather than adventuring out into the surface world. Of course this no longer applies to Ursula as she was forced out of said community and into the surface world where she had to raise her daughter.

In a similar sense to Mal, she has inherent magic coming from her mother. While you could make a case for warlock based on the shell necklace, the use of tentacles in D2 and D3 feels closer to inherited magic.

Unfortunately with Storm sorcery, it relies more on wind and lightning rather than water. I searched and searched for something to better fit her water abilities but alas I couldn't find any.

We see time and time again Uma effect on people whether it be her passion about VKs or the trust other port rats have in the chip shoppe being a safe enough place to store their weapons off of them.

Survival is kinda a given in dealing with VKs especially the more leader types, but we also have proof in the fact that she survived on her own for several months to even years during the time skip of D2 to D3.

Insight and Intimidation go hand in hand with Uma being basically the only leader on the port with an actual will to live (cough The Hooks cough. And Sammy doesn't count on him being a Smee and a statistical anomaly due to Hook exposure.)

I firmly believe that Ursula may not have been a good mother but by God was she not going to let her daughter not know the ways of the world. She at very least would be very educated in sea politics.

Uma wouldn't be a pirate growing up. Not with Ursula's and the rest of the Tritons family history. She would have grown up knowing the sea and benefiting off of it but her decision to become a pirate is mire based on Isle politics. How does one survive without become brutal on the Isle afterall?

One would have to try very hard to argue that Uma is not an inspiring leader

Ok so, my personal belief is that Uma is also Dr. Facilier's kid. I switch back and forth on making her and Freddie twins or Freddie being a slightly younger but still full blooded sister. (It all depends on how old I want CJ.) Thus Shadow Touched.

Weapon Master allows Uma to get a Scimitar. Also firmly believe that Uma would want to know as many weapons as possible to keep up with the Hooks. So double win.

Fun Fact: A Scimitar is what Uma used in D2, like if you look at It's Going Down that is the Swords that Harry and Uma have.

A dagger is both useful for dramatic effect and for throwing when someone annoys you.

While I believe that Uma would use a form of leather armor, leather can be extremely encumbering when moving in and out of water, thus Mage Armor.