Which is funny when you consider that Angels don't exist in the Fate universe.
That’s so strange in a world with pervasive use of sacramental artifacts and things with the “holy” descriptor being ubiquitous that everything else is true but that stuff.
Martha’s staff is from the Lamb Of God and it’s likewise considered holy.
Angels do exist in Fate, there is a conversation in one of the El Melloi books about how mages use them as the basis for certain magecraft
Demons exist too. Mephistopheles is an homunculus pretending to be one, the fact he's nowhere near as powerful as a true demon would be is the way one can realize he's not the real deal
This artist's style looks very similar to Maco SPL. Perhaps not coincidentally, Maco SPL recently retweeted one of sleepy7tz's posts. I'm not sure this would be enough to do an alias yet, but it's certainly something to keep an eye on.