In addition to the known fighters, there's a hidden dragon-man by the name of Vangal. His location varies depending upon your chosen character. Here's how to find him:

Wein: Second village to the WEST of GALFIEL
Mikhal: First town SOUTH of DANYAN.
Teiris: Second village to the WEST of GALFIEL
Leon: Village EAST of Fiend Tower
Gongos: Village EAST of Fiend Tower
Junon: Village EAST of Fiend Tower
Reinhart: Village NORTH to ESTONIA
How to Get Hayate and Shirox
North of Bozack castle there are two towns next to each other. Send your monarch to the left town and you will encounter Shirox, a somewhat powerful ninja. After defeating him, the ninja Hayate will talk to you. At your military conference, they'll talk about the incident. If your monarch knows he's part of the Dragon Force, then send him to that same town where you will duel Hayate. Whether you win or lose, both Hayate and Shirox will join you. Note:This will not work if you're Goldark.