So in light of recent shitposts in which we discover Roboute is definitely a virgin (this is canon,) I was trying to decide if he and Fulgrim were to bone down, who would top.
It is a difficult decision.
Thus I must default to Rules of Yaoi.
You may be uninitiated in this ancient text. This is understandable. Not all of us were on Y!Gallery in the 2000s.
The Rules of Yaoi (as I remember them) are as following
Seme (top) points for:
1) Being taller than your partner
2) Being heavier, broader, or more muscular
3) Having more wealth and status
4) Being older or more wordly and experienced
5) Having the biggest hands/feet
6) Being more traditionally 'masculine'
7) having a longer face (traditional BL) or squarer jaw (bara.)
There are personality aspects in play as well. It is obvious that someone more dominant will generally take the seme point, but not always.
So let us go one by one, shall we?
Height
The Horus Heresy series of books gives wildly different answers about primarch height depending on how each author felt at the time. Google AI seems to be the only thing coming up with answers, and I am gravely concerned bc Abominable Intelligence, gross. But we work with what we can find (if anyone has official sources I will update the post.)
Fulgrim is stated to be 10-11 feet tall and 'known for his height.' Another source puts him at 10'2". According to the google he was slightly taller than Horus, unless they put on armor (compensating for much Horus?)
Guilliman is listed as 9'4". Fulgrim wins the point.
Weight, Build, or Breadth
No information on weight on the googles. So we must look at the builds. Fanon Fulgrim is more of a swimmer's build, long lean and muscular and it's my understanding Roboute is depicted as more beefy. I have looked for official art with them out of armor, but was unable to find any. So let us compare some official art.
and together
For another perspective, let us look at @gh0st-nebulae 's excellent, belt only depictions.
It is difficult to exactly measure due to angles, but I made sure to make Robert's head the same size of Fulgrim's so they would be as matched as possible.
Roboute is most definitely wider. Guilliman wins the point.
Here's a link to specific posts if you want to reblog!