One key theme is personal growth. Eris, for example, goes through significant development from a wild and unruly girl to a more mature and responsible individual. Another theme is friendship, as seen in her relationship with the protagonist which endures many challenges. There's also the theme of self - discovery, as she figures out her place in the world and her own capabilities.
The main character is Eris, a girl full of energy and determination. Then there is the male protagonist who has a deep connection with Eris. There are also characters in the places she visits, such as the lords and knights of different regions. These characters interact with Eris and contribute to the overall story of the Mushoku Tensei Eris light novel.
One of the main themes is growth. Eris Greyrat goes through significant personal growth throughout the novels. Another theme is relationships, like her relationship with Rudeus Greyrat.
Well, 'Mushoku Tensei' light novels where Eris Greyrat is a key character are great. They depict her growth from a young, headstrong girl to a more mature individual. There are many exciting arcs involving her, like her training and adventures in different lands.
Hard to say. It could be on hiatus, but without concrete information, it's difficult to give a definite answer. Try following the mangaka's social media or the manga's official website for the latest.