The Gerudo Assault
The Geoglyph is found in the forest, just southeast of the Batrea Lake. It is located almost directly with of Sahasra Slope Skyview Tower and directly north of Popla Foothills Skyview Tower. The green portal appears within the forest, at the west side of the geoglyph, just southeast of the center of the lake.
"The Gerudo chief, Ganondorf, in his push to conquer Hyrule, uses a swarm of Molduga to assault the castle. When Rauru uses his powers to unleash an attack that destroys the swarm, Ganondorf notices the Zonai secret stone on Rauru's right hand. The sight of it draws a sinister smile from Ganondorf."
Ganondorf and the Gerudo launch a swarm of Molduga towards the Hylian. Rauru, Sonia, and Zelda team up to counterattack, destroying all of the Molduga as they approach. Ganondorf realizes that brute force power will not be enough. During Rauru's counter-attack, he notices the Zonai secret stone, causing him to give off a smirk. Ganondorf now knows what he's up against.