George RR Martin has contributed in his own way to Elden Ring as he helped during the development of the game for the creation of the world's lore in close collaboration with FromSoftware.
Worldbuilding, or the construction of a universe, is the process of creating an imaginary world, something that George RR Martin knows quite well as can show the success of Game of Thrones and the current popularity of Elden Ring.
The Grafted Blade Greatsword direct reference to Game of Thrones
The Grafted Blade Greatsword is obatined after defeating the Leonine Misbegotten, an optional boss that loots one of the legendary weapon necessary for the achievement. This sword doesn't hide anything and really looks like the Throne from George RR Martin's other work.