kimuchi's manga / #Nobility(4)

can anyone clarify the mana circle? i'm still a little confused to why she has been training using her mana circle. & in the novel (ch51), there's this scene after the rebellion where the ronans have a conversation about charlize. obviously they're all repenting but they mentioned how they regret blocking her mana circle when she was young. did that restrict her magic or somethn? or was it a figure of speech emphasizing their past cruelty towards her? very confused...