For your speculative needs.
Some minor details about each theme in Deck Build Pack: Tactical Masters have been revealed by a promotional poster. The theme for which we still know nothing about reads:
The comment about the set in general:
“Put your ingenuity to the test and clear (the game)!” (Kouryaku is generally just conquering, but it’s used in game strategy guides for clearing the game or a given challenge)
“Stand in formation, o warriors!
Advance through the battlefield with that courage!!”
“Valiants Assemble – Mamonaka”