Who is Ko S'la from Burmese Days and what is their importance?

Ko S'la, born in 1890, was Flory's servant since the men were both twenty years old. In their younger days, their relationship was more like that of boyhood friends, but as they have aged it has become more of a master-servant relationship. Ko S'la is an abbreviated form of Maung San Hla. Ko S'la wears traditional Burmese clothes and speaks Burmese, though he understands English. He is dark skinned,short and square-shouldered, and usually puts on a harassed appearance.