I have been putting off reading Dark Triumph simply because I read the preview at the end of Grave Mercy and it did not draw me in. While I liked the overall storyline I did not like Sybella at all.
Sybella is the main character in Dark Triumph and she is just as secretive as she was in the rare glimpses of her the reader gets in Grave Mercy. I think Sybella was to come off as mysterious and attract the reader to her that way so when her secrets were revealed the reader felt sorry for Sybella. Instead it came off as Sybella not being smart enough to deal with what was happening thus making Sybella come off as foolish and weak. This clashed with the image that was trying to be presented for Sybella and just overall made me not enjoy her as a character at all.
Beast on the other hand was just as awesome as he was in Grave Mercy. Having sworn to protect the Duchess at all costs Beast is always ready to die but instead of being bitter about it Beast welcomes it with a smile and a defiant will to take as many enemy soldiers with him.
The writing was very smooth and well done. I did see a few typos but nothing that pulled away from the enjoyment of the story. I do intend to read the Mortal Heart mainly to see what happens to the Duchess in the end and all the other characters except Sybella.