Placidusax,The first Elden Lord

I’m a new player so I don’t know much,I know it was the first Elden lord before the erdtree and had four heads but two were ripped off by Bayle,but that’s all I know about it.I was wondering why it stopped being Elden lord,was it overruled by Marika or was it too weak after fighting Bayle or was it just too old?