Alright, for the uninitiated: in Legend of the Dragoon one of the main aspects of the battle system was that the characters gained a super-mode of sorts; the Dragoon form.
[http://legendofdragoon.wikia.com/wiki/Rose?image=The_Legend_of_Dragoon-_Rose-_Black_Dragoon_Form-jpg]
Better attack strength, cool looking armor and wings, access to great magic and a hell of a defense boost for both magic and physical attacks. The trade off was that it only lasted a few turns, so one had to conserve their uses of the Dragoon form; especially for Bosses.
Now, one of the main tactics one could use for bosses was that you grinded till you filled up the gauges to Dragoon form for each of your (currently running around) party members. If you did this before an encounter, there was a command called "Special" that allowed each of your characters to turn into their dragoon forms in one turn, so you could have all of the characters in their best state and only using one character's turn! Sounds great! However, the Grand Jewel subverted that.
Not only was it able to completely nerf the Dragoon form, which was bad enough; it could delevel the party in increments of 5, give those levels back (but that was only happened late into the battle), use any magic at full power (which was very fatal to the male characters, especially given that this battle was reliant upon physical strength), AND he would heal a fourth of his HP near the end of the battle; starting the grueling process all over again.
So yeah, this guy sucked.