Jessica's beast taming affinity was so overwhelmingly powerful that pretty much she could have four dead weights on her team and still have an answer for just about any situation. Her behemoths we land based, but they could fight in water as well. Not perfectly, but most opponents in the water would be mince meat.
The amazing part of Jessica's battle strategy was that her behemoth's had the ability to take on human form. Which meant that every technique and adaptation that humans had adapted for fighting in various environments would be available for them.
It wasn't possible to be the best in every circumstance, but with their adaptability Jessica could be confidant wherever she went.
Still Gordon was a little uncomfortable to find that Cassi's affinity didn't have any hard power and even soft power was lacking.
"Basically I am just here to look beatific."
She admitted it straight up and out in front.