The Titans are the rulers of the Elemental Planes. Their origins go beyond even the Lost Age, and they may simply be simply an emergent sentience to massive concentrations of ether. Nonetheless, they hold massive powers, equivalent to, and likely beyond the various “gods” of Akrylonor.
While largely non-present on Akrylonor, they hold importance as the former masters of the Dragons (including Elder Dragons). During the Lost Age they sought to reclaim the rebel Dragons, but their forces were defeated (or changed sides, as with Khazad and Mordra) and the gateway at the Mouth of the World sealed.
The Companions briefly ventured in the Elemental Planes (Mariana Belamont is even a denizen of the Air Plane rescued during their efforts), to recover powerful components for the creation of The Shard. This was accomplished by venturing through portals that Martien Endiros had accidentally bored into the Elemental Planes while constructing the Arcane Society's portal networks. This also led to a “invasion” by scouts from the Elemental Planes, which was a large argument in persuading Yvera to lend her aid to The Shard. During this adventure they encountered what they believed to be the Titans, though it is likely to have been chief servants, or minor manifestations , rather than anything resembling the true force of the beings.
There are four Titans, one ruling each of the Elemental Planes. If the Fey Plane has any sort of similar ruler, it does not act in concordance with them. While many of the Dragons rebelled and left, many also still serve the Titans (most commonly sharing the ethereal aspect of the relevant plane.
Caddarog[]
Caddarog is the Titan of Water. Controlling a world of vast oceans, with no apparent bottom or top. The inhabitants of the Plane use water dwelling plants to construct floating structures to dwell in. The Companions encountered a potential avatar of him in the Kraken, a giant tentacled creature with the armoured shell of a sea turtle.
Pharagol[]
Pharagol is the Titan of Fire. The Fire Plane is a place of vast pools of lava, and flame. The sky ends simply in a wall of pure fire. Small islands of (barely, and oft collapsing) solidified ash provide space to walk upon for those dwellers who need such. The Maelstrom, an avatar or servant of Pharagol, simply resembles a giant bird or dragon, composed of flames, and surrounded by a whirling vortex of even more flames.
Syliniev[]
The Titan of Air, Syliniev rules over a plane of clouds with no apparent surface anywhere. While denser points of air called firmament do exist, the ability to discern them is limited to trial and error, or abilities possessed by the plane's own denizens. The Vortex, the manifestation of Syliniev the Companions faced, was a blackened cloud of constant lightning and vicious winds.
Vorgas[]
Vorgas is the Titan of the Earth Plane. Ruling over a vast network of caverns, and an inhospitable surface broken chasms, dust storms, and towering cliffs and mountains. His suspected avatar was the Goliath, a hulking creature of stone and mud that simply formed from stone and moved through it easily, most closely resembling some sort of shark.