I just noticed there are three tags for the same artist; glenn_s._knudsen, blackfox85, and sebastian_glenn. What's the guideline for deciding which two get aliased away?

We usually alias an artist's aliases to the one they use most often, or are best known as.

most artists don't like us using their real names.

Blackfox85 is this artist's most popular alias, so I'll be aliasing glenn_s._knudsen and sebastian_glenn to that, then.

ippiki_ookami said:
most artists don't like us using their real names.

I'm not really sure why you had to bring that up here.

This usually also means using the alias they sign their art with, hence the "most used" or "most popular" reasoning. This is clearly the best solution and as far as I can tell is always used on e621 (when possible)