When the Blue Duke dies (possibly during the Seige of Redgorge), Gau feels personally assaulted by the loss of her Apprentice and seeks to hunt down his killers.

Gau seeks out the party either at Redgorge. She has prepared herself well using a variety of potions, scrolls and spells cast by her Cagewright allies (none of whom she told why).

Gau has the following spells cast upon her by a 16th level caster – Spell Turning, Globe of Invulnerability, Stoneskin, Protection from arrows & Bull Strength. Also note that I have replaced Great Fortitude with Great Cleave in her feat selection.

From outside the walls she issues a challenge – ‘Murderers of my Apprentice, the Blue Duke. Come face me on the battlefield or I will tear down its walls and feed upon its helpless people!’

The party will most likely be involved in business within the city and this message will be relayed to them urgently from a wall guard. When the party arrive a troop of soldiers are riding out to confront the single Minotaur while, from the gate towers two ballista bolts are fired.

The party will witness from the wall/sky as one massive ballista bolt narrowly sails over her head while the other strikes her directly in the chest causing  her to stubble slightly backwards but otherwise leaves her completely unhurt. The soldiers thunder towards the minotaur as with lances poised when the  massive minotaur roars, lowers her head and charges directly towards the surprised riders.

Gau plows through the riders sending 3 soldiers and mounts spinning through the air to land in a bloodied heap up to twenty feet away. Seemingly unfazed, the  remaining riders circle the minotaur flanking her and attempt to hack her to pieces with their swords.

Unhindered Gau will destroy the troop in a single round – attacking 4 times, using greater cleave and power attack in combination to send horses and riders  hurtling through the air in all directions.

If the party attack Gau using spells or missile weapons, she will take to the air to confront the caster/attacker directly. Gau will remain long enough to make a lasting impression then send in a great force of soldiers, Chisel members, Striders etc where she will say -  ‘Next time we meet I will be leading my army which will turn this town/city to dust after I feast upon your dead flesh’

Gau will then be teleported away to the Fiery Sanctum by Rhiavaldi.

Alternative / additional foreshadowing for Gau:

When the half-minotaur half-dragon barbarian confronts the party in chapter 7 and they chose to roleplay the encounter, they can learn about that "attractive female Minotaur" that he once met and who he'd like to meet again. Gau could also be his mother or sister.