My favorite part of Hell Follows With Us is that if you ask 15 people what Seraph represents, you'll get 15 different answers :)
So let me put my 2 cents in!^^
I always interpreted Benji's transformation into Seraph as a metaphor for the forced feminization that trans men sometimes face from their family members.
Overtime i have come to notice a few commonalities in the trans men community, almost all of us can relate in some way to having girlhood and womanhood forced upon us in some way, but often that pressure comes directly from our mothers.
I think it's very significant that the one who imposed Seraph on Benji is his mom.
And is something that he is both scared of and changes him irreparably.
It seems to me, that for a lot of women, trans men’s embrace of and desire for masculinity and rejection of femininity is perceived as a slight of some kind.
For a lot of trans men, our femininity is viewed as having more intrinsic value than we do as people.
Our long hair is guarded and valued not by us, but by the people around us.
Many of us have had the concept of pregnancy, motherhood and grandkids and marriage forced upon us by our female relatives, and have been dismissed or laughed at when we express distress over that.
(The ol’ “beauty of motherhood” and “you’ll change your mind when you’re older/meet the right man.” Argument.)
And some of us are taken and forced to under go electrolysis, should we ever show even a slight amount of chin hair, forever destroying any chance of experiencing the simple joy of shaving or grooming a beard…
The same way forced feminization hurts trans men, because like Silas show’s in The Spirit Bares It’s Teeth, it doesn’t matter how dolled up and feminin a trans man is on the outside…
a man, is a man, is a man.