I am still thinking about the mental image of Godfrey having some twisted, maybe even erotic, pleasure in battling and killing Heolstor. It just fleshes the character out it the best way possible. Like making everyone collectively finally pay attention at the Revenger from the base Elden Ring was one of the coolest things Nightreign did.
So trueeeeeeee. Honestly, it's one of the reasons why I want to believe Heolstor and the Revenger are the same person. It just adds so much to a storyline that most people completely forget by the time they get to all the Demigods, and Outer Gods, and Elden Ring, and Land of Shadow business... it's also more interesting than the Shape of Night just being some guy, even if I do understand why some people find appeal in him being a small, nameless nobody utterly broken and cursing the whole world because of it.
I personally do not see why him and the Revenger being one and the same would detract from Heolstor since he already has little lore of his own ahah. If anything, I think it adds a bit more weight to the base game's events. Besides it's better than him being a Carian or the Tarnished after Ranni's Age of Stars lol...
As for Godfrey, I have been a firm believer of him being quite twisted for a very long time now. I think something that permanently changed my view of him was learning that he was supposed to laugh maniacally after complimenting your strength when you killed him in earlier versions of Elden Ring. It just fit well with what we knew of him, how he lost his sense of purpose when all worthy enemies fell. He loves to fight to the death, and that includes his own.
Many descriptions talk about his stoicism, and I feel that's the biggest result of the suppression of his bloodlust. Not that I think it made him incapable of laughing or smiling, it just made it so battles would feel less addicting. In general, I think Serosh became the medium through which he lets out his stronger emotions so that he may keep up the stoic facade. The scene where he is holding Morgott's body comes to mind, Serosh roaring as Godfrey cradles his son's corpse and then roaring again as he prepares to fight us. But when an opponent is just too good, even that begins to falter, with Serosh having to work extra hard to suppress his primal desires by clawing and biting into him, just as he does during the battle against us. He is barely containing himself the whole time he is fighting us.
Since he was so eager to keep the memory of the Revenger somewhat alive after their clash, I am sure fighting him had the same effect. I can picture Serosh trying really hard to keep his bloodlust in check after he defeated him at first, so he could offer him a place in the Erdtree's armiy for his impressive strength and courage, even though Godfrey earnestly wanted the duel to end with one of them dead. And so, when Heolstor charged once more, spitting upon his vile offer to serve, cursing him, his God, the very world that would allow such monsters to rise to power, Serosh was forced to let go and give the Elden Lord what he truly wanted... and that's when he cleaved him in half, leaving him with his iconic gash. In the end, Godfrey knew the unknown knight wouldn't have had it any other way either. And so that day the Lord had a very odd, toothy grin on his face, one that only the beasts he hunted in his youth, his loyal Crucible Knights, and Queen Marika herself had seen before then...
