Apparent Competence [Deception]

Requires Fake it ‘til you Make it Feat

When attempting to don armor or
wield weapons with which you are not
proficient, you can attempt to appear
proficient, ignoring disadvantage on
your attacks and other pentalties due
to wearing unfamiliar armor and
adding your proficiency bonus to
your attacks with the unfamiliar
weapons. This effect lasts for
10 minutes and you regain
the use of this ability after you
complete a short or long rest.

Next Rank /Heart of Treachery/