Major-General Sir Herbert Benjamin Edwardes was an English administrator, soldier, and statesman active in the Punjab, India. He is best known as the "Hero of Multan" for his pivotal role in securing the British victory in the Second Anglo-Sikh War.
Edwards' extensive work in India could suggest that he is a previous adversary of Henry Green and Arbaaz Mir, who has returned to London to secure Templar power and combine a collection of Pieces of Eden with the Koh-I-Noor. Comments from the developers insinuate that there will be "Multiple Pieces of Eden", and the Templars might possibly need the Koh-I-Noor to bind all the fates of these pieces.
This could be an applicable reason why Edwards travelled to India in 1841, to obtain the Koh-I-Noor while the rest of the British Templars find other POEs, such as Lucy Thorne with the Shroud, or oppress the working class through gangs, such as Bloody Nora. Edwards being a Templar could also add emotional tension to the story as Edwards and Green may have some personal resentment they didn't get over in India. It's also feasible to think that Herbert Edwards is the Grand Master of the British Rite of the Templar Order during the events of the Syndicate, because he died in 23 December 1868, which probably means he would be the last target in the game.
A paragraph from the Arbaaz Mir page: In 1841, two years after Singh's murder, relations between the Sikh Empire and the British Empire became tense as the pretenders for the title of Maharaja battled for supremacy. During that period of turmoil, Arbaaz was tasked with recovering the Koh-I-Noor originally belonging to the Assassins but then in possession of a newly arrived Master Templar. While investigating the matter, the Indian Assassin also tried to protect his friends and lover from harm.