I chanced upon this shot by CJ in Panti forest (2013) and I'm certain that this is Arhopala avathina.
http://www.butterflycircle.com/showt...013&highlight=

The original caption:

Arhopala ___? (Subject was really tiny)


It meets all the criteria clearly.

- The size description is enough to narrow it down to a muta-subgroup species.
- HW post-discal band completely dislocated at vein 2. It can now only be muta, moorei, metamuta or avathina.
- Sub-marginal spots dark and unsually well defined, even in this worn individual.
- FW post-discal spots 3 and 2 more or less in line, spot 2 slightly shifted inwards compared to 3; post-discal band shape corresponding with holotype.

The green tornal metalmark is broad but this marking is often variable.