Epic! is an ebook and audiobook provider, primarily used by schools. They've started producing some of their own books, via Andrews McMeel (they are probably familiar to most librarians as the publishers of comic collections and series like Phoebe and her Unicorn and Big Nate).
I looked at two samples from their early chapter books. The first, Problem at the playground, is a little mermaid mystery. Violet, the daughter of the mayor of Aquamarina, and her best friend Wally the narwhal, are excited to see the new playground. But all the screws are gone and the playground is destroyed, much to the disappointment of the crowd and the the leader of the engineers, Ms. Rivet Rogers. Violet and her friends investigate the mystery and solve it, finding the real culprit after suspecting prankster Gill Sharkfin, a mischievous merboy. Colorful digital illustrations show a variety of merpeople with skin colors ranging from brown to purple. There are short sections afterwards, talking about the science of engineering and some of the sea creatures mentioned. The text is fairly simple and the font large - about on par with Kitty Princess, Critter Club, and other beginning chapter books.

The secret of shadow lake is a slightly higher reading level - closer to Magic Tree house. It features Norm, a Bigfoot boy who is not happy about having to attend Camp Moonlight after having gone through a growth spurt that has made him uncomfortably tall as well as other hormonal changes. He feels better when he meets up with some other oddball campers; Oliver, a small and nervous human (the only one at camp), Hazel, a hyperactive jackalope, and Wisp, a small fairy with one small wing who can't fly well. They decide to work together to overcome their individual difficulties and pass their canoe test, but there's a cartoonish villain lurking in the background, eager to kidnap Norm for his museum! This had more fully fleshed-out characters, albeit somewhat cartoonishly portrayed, but the lengthier text gives more room for detail of course. The illustrations are fewer and more cartoonish than the mermaid story.

Both series are available in paperback and hardcover, which I assume to be paper over board because of the price point. However, the books I borrowed from another library had a slightly different ISBN than the hardcover. The covers felt and looked like a prebound copy, but the joints of the binding were already separating and I didn't see any indication of who had done the binding. It's too small a library to have full cataloging either, so that will remain a mystery!
Verdict: If you need more fill-in beginning chapter series, both are acceptable. There are plenty of better books out there, but if you're going for quantity, these are attractive, humorous, and have nice hooks that will grab kids.

Problem at the playground: ISBN: 9781524855475; Published October 2019

Secret of shadow lake: ISBN: 9781524855468; Published October 2019