This guide will include all units that can not be obtained by the player as well as major enemy encounters. This page contains major spoilers for the game.
Unattainable Units
Grappler
Knight Templar
Daemon
Knights of Danika
Major Mission Bosses
Quass Debonair
General Godleslas
Rhade
Ankiseth Gallant
Liedel Klein
Baldwin Glendale
Pruflas
Biske La Varet
General Kerikov
Xevec
Diomedes Rangue
Prince Amrius
Vapula
Amazeroth
Carth Forleizen
Silvis
King Procus
Prince Yumil
Thamuz
Richard Glendale
Danika
Every Zenobian
Grozz Nuy
Grozz Nuy is a special boss that is required to unlock the Dragoon class.
To get the Sword of Tiamat:
"After you have gotten both the Dragon Helm and Armor, return to Mylesia, Idorf and get info about the Sword of Tiamat.
Get the Dragon Scale and Divine Dragon info at Fair Heights, Elaine after mission 21.
After mission 24, your unit leader will fight a dragon in Celesis, Pinneg. You will receive the Sword of Tiamat as a prize."