The Togatl Grounds is point of interest located within a hylek village inside a cavern within the Viathan's Arm area of Kessex Hills. Due to the ettin blocking their food supplies, they are all starving.
The only entrance is via an underwater tunnel in the Eukaryan Caves area of Kessex Hills. From Matlal, the Renown Heart NPC, go underwater and a little northwards until you locate a nearby underwater-cave entrance. Go down into the underwater-cave, north-east through the underwater-tunnel, until you must go back up to the surface.