Yun Crimsonrain is a character from Unlimited Saga. He owns a shop in Loch Vaan and is Norff's master. In Armic's quest he decipher's Iskandar's Magic Tablet to uncover the location of the items needed for the ceremony.
When Yun finishes deciphering the Tablet, he tells Armic that the location of the final item is The Flying Island, one of the The Seven Wonders. There Yun appears as the final boss of Armic's scenario, thinking that if the Chapas are allowed to decipher the Tablet, they will cause unforseen destruction. He must have seen the error of his ways upon his defeat ,however because he is present in the ending of Armic's scenario.
His role in Kurt's scenario is brief; with him begging Kurt to take Norff into his party for training if he visits the Loch Vaan Magic Shop.
As A Boss
Yun, like Clyde, is a boss centered around Magic. He will only use Magic against Armic's party, such as Fire Arrows, Thunderbringer, and the like. While much his arsenal is identical to Clyde's, Yun himself comes with a gimmick. Once the battle starts, he will surround himself with a forcefield. He is immune to all forms of damage while the field is active. To break the barrier, the party must cast spells pertaining to four specific Elements in a set order. Once broken, Yun will begin using more aggressive spells such as Seal of the Abyss, and will gain a new attack: The Forbidden Spell, which deals no HP damage, but will chip away 1 LP per character it targets.
Being a Magic-caster, he can interrupt Combos easily. The best way to deal with Yun is to play it safe until the forcefield is broken, then launching an aggressive physical-based counterattack.
For all the lines of the character, go here:
Yun's ultimate attack in the fight against him is none other than the Forbidden Spell; implying that he either found the Magic Tablet of the Forbidden Spell prior to the game; or found another method of obtaining it.
Yun is also the only boss requiring a special condition to defeat.