Roparde - He's in the first room of Old Vicalle Mines, if you haven't already fought him.
Schweiss - Xailen Woods.
Gatrega - From Xagut Floodmeadow - Northeast Region, take the southwest exit to find it.
Folzam - Climb up Bermia Gorge. Once you get next to the Memory Ring, head for the Northwest Region and climb up as far as you can to find him.
Melanbron - Go to where you fought Volt, the roof of Helioborg Fortress.
Dranzort - Tatalian Abyss