The story is interesting and dense. Even though it's only one hour long, it feels like it lasts way longer because of how many things happen and the excellent atmosphere. Just like in the main anime, not everything is explained completely which leads to an air of mystery. There's also some minor worldbuilding with new concepts from the world being introduced.
The characters are detailed and very realistic. Of course there's Chise and Elias as main characters but in this OVA a human boy named Gabriel also plays a big role. His personality and relationship with his parents is very realistic which added to the story and I felt like it made it easier to get immersed in the story.
The voice acting was good and the same as in the main anime. The animation was good but the music especially was great. The music suited the animation well, brought about an air of mystery and made watching this a nice experience.
Overall this OVA is definitely worth watching if you enjoyed the first season. It is a sequel, relevant to the main story and just has a great story with good animation and music.
