Hades is the realm of Death. Also known as the Underworld, the Abyss. The gates to the Underworld can be opened anywhere that water flows into the earth, if a mixture of blood and water is poured into the flowing water, and a specific rhyme is spoken. A place where the gates can be opened lies near one of the Dragon Pillars in Silmaria.
The Elysian Fields of Hades is located there.
Hades may be physically attached to Gloriana, as it is said that all rivers that flow in the earth flow to Hades... Thus there are likely many gates near rivers that flow into the Underworld.
Behind the scenesEdit
Logos refers to Hades as "Hell", but a message within Hades, says its "Hades, not Hell". Hell is the home of the Demon Wizard. Likewise the term 'underworld' can refer to various afterlives including; Tu-at, hell and Hades.
At least for the sake of Hades, the term Underworld, appears to denote that Hades is physically located under the earth, below the surface of Gloriana.