The River Styx
The River Styx – also known as the River of Hate. Well known in legend as one of the five rivers that separate the mortal realms from Hades or the Realm of the Dead. There are tales of individuals becoming invulnerable and therefore immortal by bathing in its foul waters. But there are rumored to be significant side effects that make such an undertaking undesirable. Still, it may offer an option if no other is available.