Zettai Bouei Leviathan

Both shows have similar fantasy themes to it. Main characters either just have fun or go on an adventure/quests like fighting bad guys, etc from time to time. As a bonus, the girls in both shows also have transformation scenes! 

Both anime are mahou shoujo anime, set in a fantasy world, with a very similar sense of humor. Zettai Bouei Leviathan feels much like an homage to Magic Knight Rayearth, most noteable if you compare Syrop and Primera. 

Cute Girls Doing Cute Things in a fantasy setting. 

Same producer (GREE) and also very interesting and also a show for kids. 

Both are set in an alternate world and are concerned with the protection of that world. They also share a likeness in having a cool, relaxing atmosphere with snippets of action added in.  

Both have a fantasy setting, similar art, have magic elements and are quite relaxed in pacing. 

Both animes take place in a fantasy setting w/ dragons. and as an added bonus much like how the girls went into the dragons body in That Time I got reincarnated as a Slime has a dragon being absorbed by a Slime's body 

Both have cute moe designs and a Kana Hanazawa voiced character who speaks her mind and says inappropriate things. 

To protect the world, the characters must work together to defeat the evil that has arisen. “Zettai Bouei Leviathan” and “Onigiri” have some type of unknown force that threatens the planet. Moreover, the characters in these anime are a bit dysfunctional with each other. However, as time goes on, they start to set aside their differences and work together as a team. Not only do these two have similar characteristics, the two shows don’t really take itself too seriously giving that comical feel you’d hope to expect. Also, they’re based off their own games. If you’re looking for a light-hearted fantasy anime that derives its source material from a video game, then these may be for you. read more 

Lighthearted shows, enhanced by amazing voice acting, colorful backgrounds, cute character designs, and enjoyable fanservice. 

Both series have almost all-female casts (at least, all the main characters are female), and feature magical girls trying to defeat a mysterious enemy. Leviathan is more light-hearted, with more fanservice, and takes place in a fantasy medieval-ish setting, though. 

A group of travelers set out on a adventure. Ridding the world of a mysterious force.  

Strong voice acting, cute character designs, and a lighthearted atmosphere define these magical girl anime. 

Both adorable in some ways, with incredibly clueless characters with similar levels of humor 

Nice character designs, a little bit of action, and some enjoyable fanservice. Additionally, all the main characters are cute girls and there are no male leads.