I find it interesting that Russ was about the only Primarch we see Valdor interact with that he actually likes. I think Lion and Valdor are very similar in personality and by the time of the Scouring they both are really close with Russ and not much of anyone else.
Don’t want to throw out any spoilers, but if you haven’t been reading the Bequin trilogy it’s interesting. 🤔 Can’t wait for the last book to see what is actually going to on.