Very difficult.

The closest match appear to be Arhopala arvina.
Ssp aboe usually have the HW spot 6 with the outer margin notched.
https://species.wikimedia.org/wiki/A...ille1895OD.jpg
https://en.wikipedia.org/wiki/Arhopa...oeFUpUnAC1.jpg
https://wingscales.com/Lycaenidae/Arhopala-arvina-aboe

This drawing shows one with HW spot 6 with rounded margins.
Probably ssp ardea from Assam & Khasi Hills.
https://species.wikimedia.org/wiki/A...tson1863OD.jpg


Tl Seow: Cheers.