A RAINBOW OF PASSIONS
This Thirty Years' War-themed AU focuses on the relationship between Renly Baratheon and Loras Tyrell, here portrayed as the rittmeister and lieutenant, respectively, of the same company at Sweden's service. Margaery Tyrell is Renly's childhood friend and fiancée (later, his spouse), consternated when he dies of wounds inflicted at Lützen, and feeling powerless not to have been able to save his life.
The Lannisters are Austrian courtiers who have managed to arrange Wallenstein's demotion, and the villains of the piece (Jaime is the Kaiser's corrupt confessor!).
Another, more featured antagonist, is Stannis Baratheon: here a devout Catholic, whisked away and raised by Jesuits as a child, a colonel on Tilly's (and later on Wallenstein's) side, keeping the religious vows in camp like Tilly. There is something personal between Stannis and Renly: the former blames the latter for their older brother's assassination during the Pfalzic phase of the war, in the 1620s (Robert was a Lutheran, like Renly). Thus, Stannis becomes the one who slits Renly's throat at Lützen... but such a deed won't be left unpunished.
Roose Bolton and his son Ramsay also appear as wardens of Küstrin, and later as wardens of Ingolstadt, to reclaim Küstrin in the end. Roose is one of Tilly's closest officers and an inquisitor. Theon Greyjoy, the lieutenant in Robb Stark's company, left for dead at Lützen, is here subject to the Holy Office's most relevant methods.
Catelyn Stark is a military widow and camp follower. Her daughter Sansa is abducted and brought to the Hofburg by Joffrey Lannister, while Arya gradually becomes a skilled marauder and Robb, another rittmeister and frenemy of Renly's, is killed (by Roose Bolton, obviously) at Lützen.
Jon Snow is a highwayman, partnered with red-haired robber girl Ygritte, who once fought on the Protestant side. His path finally crosses with Arya's, and with that of Brienne, the ensign of Renly's company, who has escaped the firing squad after being scapegoated for the death of her commanding officer: both girls join his crew.