is being a black angel for halloween worship the devil?

[Tofu]

nothing personal intended --
i'm merely attempting to "think this thru in writing",
to sincerely find an answer to your question...

if it were me (its not "me), i'd ask myself if i worship the devil now.
i don't; i don't believe in two, spiritual forces.
but regardless of anything, that's besides the point.
if i dress like a devil character, it doesn't mean that i am worshiping (honoring) one.
nor does it mean that i become the literal meaning of the costume.

in the same way:
if i dress like an ancient Greek goddess, i am not worshiping her ---
especially because: hey, i really don't know the ancient, Greek religion that well;
the costume itself, has not changed my spirituality nor
the rest of my original "self" in any way.

when my girlfriend's son was a boy, he loved an evil-looking,
gargoyle night-light. he was afraid of the dark otherwise --
but neither my girlfriend or her boy thought twice
about any belief-in gargoyles or worship of them.
(at one time in history, gargoyles were widely considered
real protection against evil & mishap.)

we know how
kids express & seem to want the most-outlandish things;
the boy's night-light looked like a demon or something;
but rather than worship, it was all in fun.
...just like a Halloween character.

or if a guy dresses like Santa Clause,to become a favorite of children
at the mall's department store around the Holidaze...
he isn't worshiping Santa -nor believing in him or Mrs. Clause.
the guy very likely: loves the kids' excitement; needs the job; and enjoys this one
(or he wouldn't have considered applying for it).

i always took my little boy to see Santa.
and when my boy dressed-up for Halloween (usually a skeleton or devil) --
real belief and/or worship never occured to us.
for one thing, neither he nor i would've understood anything about "worshiping"
the nature of his one-night disguise.

for last Halloween, i dressed in authentic costume as
Egyptian Pharaoh-Queen, Hatsepshet --
but tho i admire Ancient Egyptian culture,
worship had nothing to do with it.
i never became "Hatsepshet" or worshiped her;
and life went back as it had been beforehand.

regardless of how Halloween originated,
it's still thought-of as entertaining for most
in today's culture. people usually have fun with it.
of course there are those who don't for whatever reasons,
including because of religious beliefs/fears.

if a person somehow feels disturbed about
dressing-up in a costume of a black angel (ie, devil?)
for Halloween...
if they feel their God will punish them for some reason...
then by all means, these folks are the ones
to re-think their participation in Halloween
(and perhaps other Holidaze too.)

sincere thanks for considering my personal thoughts/opinions.
hopefully i have been able to help you -- in some way -- with your question.
best wishes, Friend!