Just finished the book, enjoyed it. More than the previous Helbrecht one.
No spoilers but I enjoyed the High Marshall personal journey trought the story. Other 2 protagonists, Elysian and Squat have a solid part on the story aswell.
Overall a good Black Templar book, in my opinion. Of the recent ones, Broken Crusade and this one, are solid picks.
Edit: Helbrecth thralls are mentioned a few times, apearing once in a while to clean his weapons. It seems they just acompany him everywhere.