Prior to becoming a Nazgûl, Suladân was a noble king of the Southern lands of Middle-Earth. He once warred against Sauron, recognizing the danger he posed and determined to stop him. Unfortunately, when Sauron surrendered to Suladân, he duped the young monarch into thinking that he'd won. In reality, Sauron set himself up as Suladân's "advisor" and began steadily corrupting him, a corruption that was completed when Sauron gave Suladân a Ring of Power, which turned him into one of the nine Nazgûl.
As a Nazgûl
After being turned into a Nazgûl, Suladân was reduced to doing the bidding of the very entity he'd once thought he'd conquered. Come Talion and Celebrimbor's forging of a new Ring of Power, Suladân was dispatched with the other Nazgûl to deal with them, and ended up being the first major Nazgûl Talion would do battle with.
- Coincidentally, Suladân shares a name with a minor character from the Lord of the Rings Strategy Battle Game, Suladân the Serpent Lord. However, that character was a Haradrim vassal for Sauron in the Third Age and proudly loyal to him from the start, whereas the Suladân in this game was a king from an older time who was initially good, before being suckered by Sauron into taking one of his Rings of Power. Since Monolith Studios has repeatedly stressed that Suladân is an original character on their part, the identical names should be taken as mere coincidence.
- His being a king who was corrupted by a seemingly defeated and captured Sauron that had set himself up as an "advisor", brings to mind the similar story of the Numenorean king Ar-Pharazon, who suffered the same fate (though he did not become a Nazgûl). This makes Suladân the second great king of men who Sauron corrupted after surrendering and becoming his prisoner and then "advisor".