Cfrtjryk

What I am really looking for is "some entity who does not belong to certain domain but happens to possess the traits of the entities from that domain". The entity, traits, and domain can be anything.

For example, a foreigner can share similar value/custom/preference with the locals.

Any answers from abstract to specific are welcome. I will conduct further investigation to find the appropriate word which fits my specific context.

Here are two examples in which I think the phenomenon you are describing can happen. I believe it can generically be referred to as convergence, from the meaning of to converge:

gradually change so as to become similar or develop something in common.
(Oxford Eng Dict)

1. In the realm of biology, the wings of a bat are an analogous structure to the wings of birds. This phenomenon is called convergent evolution.

Convergent evolution is the independent evolution of similar features in species of different lineages. Convergent evolution creates analogous structures that have similar form or function but were not present in the last common ancestor of those groups. (...) Functionally similar features that have arisen through convergent evolution are analogous, whereas homologous structures or traits have a common origin but can have dissimilar functions. Bird, bat, and pterosaur wings are analogous structures, but their forelimbs are homologous, sharing an ancestral state despite serving different functions. (Wikipedia)

2. Linguistic typology is another example in which one may group together languages which are not related by their history. E.g., morphological typology will qualify as fusional languages as diverse as Greek, Hungarian and classical Hebrew.