  In the past, the study of the divergence structure of the holographic
entanglement entropy on singular boundary regions uncovered cut-off independent
coefficients. These coefficients were shown to be universal and to encode
important field theory data. Inspired by these lessons we study the UV
divergences of subregion complexity-action (CA) in a region with corner (kink).
We develop a systematic approach to study all the divergence structures, and we
emphasize that the counter term that restores reparameterization invariance on
the null boundaries plays a crucial role in simplifying the results and
rendering them more transparent. We find that a general form of subregion CA
contains a part dependent on the null generator normalizations and a part that
is independent of them. The former includes a volume contribution as well as an
area contribution. We comment on the origin of the area term as entanglement
entropy, and point out that its presence constitutes a robust difference
between the two prescriptions to calculate subregion complexity (-action v.s.
-volume). We also find universal $\log\delta$ divergence associated with the
kink feature of the subregion. Similar flat angle limit as the subregion-CV
result is obtained.
