This is one of the largest species of the genus Arhopala, which comprise over 80 species in Malaysia and Singapore. Many of the species are difficult to identify in the field and careful entomological study is required to accurately separate the species. The Centaur Oakblue can be differentiated from the other Arhopala species by the slivery green lines edging the markings in the cell on the underside of the forewing.

The male is purple-blue with a very narrow black border on the forewing. The paler and more purple female has broad dark borders. The species has a symbiotic relationship with ants during its larval stage. The green caterpillar has a brown saddle mark. The caterpillar is attended by ants, in particular, the 'Fire Ant' or Kerengga (Oecophylla smaragdina). The caterpillar exudes a honey which is 'milked' by the ants in return for protection. No predator would normally risk tackling these aggressive biting ants to get at the caterpillar.

The butterfly has been observed both in the nature reserves and in areas outside where its host plant and the Kerengga ants abound.