- "Run, run, little boy. "
- ―Bastien to Pierre Étienne, 1789
Bastien came from a distant branch of the house of Braganza , but his father lost all of his money after a series of wrong-invested transactions. Bastien's childhood was all with luxury, but his youth with slum. As his family-members had to hit the skids one by one, Bastien soon became a victim of sickness. Because of this, he was brought to the edge of despair – making him mad, and later sent to the Salpêtrière Hospital in Paris, where he lived for several years.
Breaking out from the hospital at the edge of 23, Bastien had already became a murderer – responsible for the death of ten innocent men and women, 20 totally. Bastien had arranged a massive breakout with the help of several others desperate souls within the hospital – promising them justice and peace. After the breakout, he was soon brought to justice himself – hunted by Assassins. Bastien knew his life was in danger after the breakout, and lived in constant paranoia – so, he sought for help from the rising politician Bourienne. The man, secretly a Templar, promised to hide Bastien from the Assassins if he chose to join his group of mercenaries, clearing out his way for Bourienne. The Templar's offer was quite simple: join his forces to be killed later by his own clumsyness, or be killed anytime by some hooded men and women. Bastien accepted to join.
As a mercenary, Bastien's task was to make sure his employer did not run into ghosts of the past or future threats. His base of operations was soon in Calais and sometimes in the city of Rennes. In 1782, Bastien and other mercenaries working for Bourienne was sent to Rennes: Bourienne was to carry out some transactions for the Templar Order, but some Assassins seemed to wait for him. Bastien and several of the mercenaries would get paid a lot of money in order to remove the threats. Killing the Assassin-leader, Bastien would be stationed in Calais with much money to go with. In the city, he would work alongside the Droit-siblings and a monsieur Babineaux, where they would be the leder of the mercenaries.
During Bastien's time in Calais, he and his associates became known with the leaders of The Turk, an organization established by the Templars: Shamar al-Djin and his Board. Through one of the lieutenants of al-Djin, Loïc and the mercenaries were allowed to stay at a pub. From there, the mercenaries would eliminate enemies of The Turk, carrying out work for them also. As a mercenary, Bastien's loyalty lay were the money was. This lead to his downfall. Loyal to both The Turk and Bourienne, Bastien and his associates stayed at the pub where lieutenant Murat ruled – even after her death. A few days later, an Assassin entered the locals. Bastien and the other leaders of the mercenaries took an interest in him, and later they followed him out of the building. After threatening the Assassin, the man turned around quickly – shooting monsieur Babineaux in the head. After killing him, the Assassin soon wounded one of the siblings, then moving over to Bastien. Bastien fought aggressive, but the Assassin made an end to that with his sword. While Bastien was dangerous to fight close with a weapon, the attacker used his sword to disarm the man; he then pushed his rapier into the mercenary's stomach, and so placing his hidden blade into the man's neck. After killing Bastien, the Assassin soon ended the life of the siblings.
- Bastien is a short form of Sébastien – meaning "from Sebaste"
- Bélanger has its origin from the French given name Bérenger – from the Germanic Berengar, meaning "bear" + "spear"
- Bastien was a Templar puppet – he never knew about the Templars and the Assassins, but he supported Order however (unknowingly).
- Bastien was targeted by the Brotherhood because of his violent nature and crimes at the Salpêtrière Hospital