This series is really interesting! Unlike other 'villainess' stories, Tia really feels like a true villainess--she plots and is willing to dirty her own hands (although for the ultimate good). I also love how this manga adopts a 'show not tell' approach. Tia is shown as a great strategist through her actions, and not just mentioned as a genius without much to show for it.
On another note, the trans corner at the end of the chapters are always awesome. Its amazing how the team can pick up the little details the author puts in and its always a joy to read back to the hints ^^