Incredibly Trill Monster Location - Borea's Lost Ark Gold Domain
Go north starting at The Forlorn Camp Triport and move west to the south of the two large areas of the west-side of the Borea's Domain map. When you reach the area keep to the south side of the map and move toward Southwest corner. You'll be able to find your Merciless Trill.
Scherrit Army Gladiator Monster Location - Sunbright Hill
To reach the Pumpkin Farm Triport, go directly south into the Remnants Assembly Area. Follow the central route into the area and pass by Hank's Tara'a Hank. At the end of the trail near the sunflowers, there is The Scherrit Army Gladiator.
Sturdy Red-Eared Mythical Monster Bird Location The Dyorika Plains Plains Dyorika Plain
Follow the route to the northern part of cheapest Lost Ark Gold Dyorika Plain, to Monterque Mine. After crossing the bridge, which is made of wooden that leads to the mine follow the left fork until you reach the back. You'll arrive at an intersection and the Sturdy Red-Eared mythical bird will be right there, just at the entry point to the northern branch of the path.