Board Thread:Questions and Answers/@comment-112.208.245.31-20191012105220/@comment-44254155-20191117214520

nah it hasn't been proved really. basicly a part of Eugeo's soul remains in the blue rose sword from when Cardinal fused them together and when Tisne interacted with the sword, Eugeo interacted with her.

Sorry, trying to make it make sense for those who have seen the anime but haven't read the light novels but not spoiling anything at the same time