The Geas is a relatively obscure form of contract that was developed nearly three centuries after the formation of the Empire. Its widespread use is mainly restricted by the prohibitive material costs required.
A mind crystal shard is embedded in a vital point of the subject's body, usually the heart. The Tamer performing the ceremony is then required to link the subject's mindscape with the shard, letting the subject's mana fill the crystal and providing a trigger condition for its detonation.
The Tamer must be at least at Tier 4 in order to successfully create a Geas, which is at its core an inferior version of the Tier 5 Contract magic.
- The Book of Bindings, Matthew Freeman, Prime Minister of the Regiis Empire
Ceres dreamed.
She dreamed of her childhood at the orphanage. Cossetted away at the heart of the Akaishi Mountains within the territory of the Kitsune Daimyo, the institution that took her in was the only one that served the town they were in and the surrounding villages.
Life in the mountains was tough and every year new orphans were delivered to the orphanage.
She was just one of them, brought in when her mother had perished in a landslide caused by one of the frequent earthquakes in the region when she was out picking herbs.
She had never seen her father as she had apparently been born of a tryst between her mother and a passing traveller who had stopped at the inn she was serving at as a barmaid.
The days after she had exhausted her tears for her departed mother were the best in her short life.
Her fellow orphans were extremely welcoming and friendly, supporting her through her grief, while the matron was strict but kind. She fit right in, waiting for the day someone would adopt her.
Until one day, she fainted during her chores. When she woke to the concerned faces of the matron and the other children, she realised that there was something different about her.
As she stretched her hand out, it began to smoke, catching the rays of the sun that streamed in through the windows, making it seem ethereal.
That was the day she learnt that she had the blood of nobility flowing within her veins.
The matron was extremely excited as this meant that the orphanage would come to the notice of the Daimyo and they would finally receive funding. She could now expand the scale of operations.
Ceres was quite overwhelmed by her uncharacteristic show of affection and being referred to as her little princess and her lucky star.
But, she was extremely excited too. The matron had informed the local Tamer and he was supposed to pass the message on. They would come for her soon.
At that time, her idea of nobility was restricted to the only picture book in the orphanage. The old, well worn tome was nearly falling apart due to the residents of the orphanage reading it year after year.
It narrated the tale of a farm-girl who decided to sacrifice herself to alleviate the droughts that plagued her homeland. Her selflessness moved the Water Daimyo's son and he answered her prayers by bringing rain to the village and taking her as his bride.
She tossed and turned in her bed for a long time that night as she let her imagination run wild before finally succumbing to exhaustion.
She woke to uncomfortable heat. It was as if someone had turned the brazier in her room to full heat. The sultry atmosphere was suffocating.
Clambering out of her bed, she blearily walked towards the door of her room. She needed to let some fresh air in.
But, before she could open the door, it was shoved open from the outside.
There, outlined by the flickering light of the flames that burnt behind him, stood an extremely tall man in black robes. His face obscured by a demonic mask and his eyes that were visible through the eyeholes seemed to glow red as they reflected the light of the flames.
It was only now when the door was open that the screams reached her ears.
She stood there, stunned, until the man stretched out a hand for her.
She screamed.
And awoke with a throbbing headache. Gasping for breath, she quickly took in her surroundings.
Wooden walls, low ceiling, window with a view of the lake. She was in the home of Phobos' parents.
A sharp jolt of pain ran through her skull as she sat up. She hissed in pain as she held her head. The memories of the previous night trickled back.
So that was what had happened. Forced to use the amulet without proper preparation, she had ended up cracking her mindscape with the backlash.
She tuned her head gingerly and took in her appearance in the mirror on the dressing table by the bedside.
She looked worse for wear. Her skin was pale, her lips chapped and her hair frizzy. There were dark circles around her eyes from her fitful sleep.
She sighed. Life was harsh.
The sound of rapidly nearing footsteps interrupted her self-pitying. The door swung open and Mars entered with a tray which had a teapot and a cup.
"I didn't have the proper containers so I had to make do with the tea set. I hope that it washes well otherwise Uncle and Aunt will be tasting medicine in their tea for the next few days." He said with a smile.
Taking a seat at the edge of the bed, he set the tray onto the bed and poured out an emerald green potion into the cup from the teapot before offering it to her.
"Drink this. It's good for the pain and will help you heal faster."
She studied him silently for a moment before taking it from his hand.
She raised the cup to her lips and took a sip. Her eyes widening as the bitterness she expected didn't arrive. Instead, a mellow taste suffused her mouth, the bitterness having been masked by the honey that had been added to the medicine.
Her head snapped up to look at Mars, her eyes widening in surprise. From her knowledge of alchemy, she knew that it was a precise science, every modification a result of countless trials.
No one would spend so much time on altering the taste of perfectly functional medicine. Except, that is, someone who didn't want his wives to suffer the tiniest grievance.
She could easily imagine Mars spending hours over his alchemical cauldron so Phobos or Deimos would never have to taste bitter medicine again.
She looked down, laying a hand over her heart. An inexplicable feeling rose within her, causing her heart to clench. She could feel its rhythm as it beat. She could easily imagine the crystal shard within pulsing in tandem.
The Duchess' words resounded in her mind:
"Your mission is to marry him, win his trust and support him to the Throne. Succeed and you shall be free, or as free as it is possible to be in this world of ours. Fail, and you shall die."
When she looked up, her mind was made. She wanted to live.
"Husband, we need to talk."
Some backstory. Art for this chap is up on discord.