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.
In Armic's scenario, Yun meets Armic after his apprentice Norff introduces them. Armic wants Yun to decipher Iskandar's magic tablet, which contains the secrets to the Rainmaking Ceremony that the Chapa Tribe needs to end their drought.
While deciphering the tablet, Yun comes to find out that it holds the secret to not only a Rainmaking Ceremony, but the power to control the elements themselves. He continues to study the tablet obsessively while Armic gathers all of the items needed to perform the ritual detailed in the tablet.
Once Armic has collected all of the items but one, Yun tells him that the tablet says the final item is in the Flying Island of Avalon, one of the Seven Wonders; however, this was a lie to trick Armic into bringing all of the needed ingredients to a place of power. Yun places the final item in the center of the island where the power of Chaos can be harnessed, and allows Armic to find it.
When Armic arrives, Yun lies to him once more to trick him into handing over all of the items needed for the ritual. When Armic objects to him using the items for something other than the Rainmaking Ceremony, he threatens to kill Armic, and they battle. Upon his defeat, Yun summons Chaos in his rage.
Chaos absorbs Yun and his magical power, but after Armic and his friends defeat Chaos, Yun is returned safely to Avalon. Armic shows Yun compassion and forgiveness when he apologizes for his actions, saying he had only wanted to become more powerful than Leith Torles, and things seemed to get out of hand.
Yun returns the items and Iskandar's tablet to Armic, allowing him to return to Chapa to complete the Rainmaking Ceremony.
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.