Dark mark. Does it have any effect? (Dark Souls 3)

A dark mark is needed for a better ending, go through the quest chain for Anri, just don't lock it up, there is more information on the wiki. (the quest chain itself begins with a pilgrim magician who is crying on the bridge).
Many write that she has no neg. effects, but in fact it is not. Increases the chance that it is the red phantom that will invade you.

0000Ptasha
and you become hollow, as in the previous parts you will walk with a piece of flesh.

Raibow Bitard
Why do you think this ending is the best?

Marty52
Because the guides say so. And in the secret achievements Steam is written, if that.
There are 4 of them bad, true, best and basic.

Raibow Bitard
Got it. We must read her interpretation then.

And if the quest chain for Anri failed, is there any point in going further with a dark mark or not?