They were called the Kali Panchin - The Black Fifth. The origin of the name is confused. Some say that it is because of the black fringe worn on their turban, but the pictures here show no sign of that. They did change from a red to a black kullah in 1900 but I am inclined to think that the change was made to fit the name. It is more likely that the black facings on their tunics gave rise to their nickname.
An old regiment, the 5th Light Infantry have a long list of battle honours. They fought at Kirkee and Seringapatam. In the First Afghan War, a detachment of the 5th were stationed at a fort under the command of Capt Lewis Brown. A large force of Baluchis besieged the fort and the 5th held them off for two months. A relieving column under Major Clibborn was attacked in a steep and narrow pass called Nuffoosk and defeated, so Brown had to surrender. The enemy were very impressed with the bravery of the 5th and offered favourable terms, which in this case were adherred to.
In 1914 they were stationed at Poona with a detachment at Satara. The regiment comprised 4 companies of Dekhani Mahrattas, 2 of Konkani Mahrattas and 2 of Dekhani Muslims. Their WW1 postings were India, Mesopotamia and Egypt.
In 1922 they were the 2nd battalion 5th Mahratta Light Infantry, stationed at Belgaum. They were posted to Burma in 1932 to suppress a rebellion. The 5th MLI were designated a class regiment of Mahrattas and no more muslims were recruited. Any existing muslims were not transferred but wasted out so that by 1947 when the regiment went to India, none of the men had to be sent to Pakistan.