Once you have finally obtained the Ultimate Key from Havens Above in the final part of the game, you can open a bunch of locked doors across Erdrea. Travel to Puerto Valor and open the locked door there, where you will find this Tockle.
Upon arriving in Weaver’s Peak, speak to the female NPC on the left side of the area. She tells you that since her brother came home, he has been acting suspicious, as he has been focused on being fashionable. She doesn’t believe that’s her brother and wants to expose him as the impostor he is. She suggests you go to Quester’s Rest to see if anyone has a clue on how to get to the truth. So, travel to Quester’s Rest and speak to the warrior sitting at the table. He mentions that the Bodura Grass can reveal the truth, and says to go to the third level of the Ruby Path of Doom. If you have Holy Protection/Holy Waters, use them as you make your way to the third floor.
Once you do make it, head straight north to find the NPC in question, who will be near the two side-by-side chests from before. Speak to her to get the Bodura Grass, then return to Weaver’s Peak. Talk with Tania, then toss the grass on her brother to reveal a monster. Get ready for a boss battle!
BOSS - Dud Dude
Despite being a Troll, which are usually known to just do heavy physical attacks, the Dud Dude has a lot more in his arsenal. First and foremost, he has 9600 HP, so this is going to be a long fight, and he can act two or three times per turn. If you see the boss try to use Kazap, it will always fail, as he doesn’t actually know it. That means you get a free turn of no damage, so take it when you can. Dud Dude will also waste a turn sometimes by trying to impress Tania, which is always a good thing. As far as the actual offense goes, there is Crackerwhack, a physical attack that hits the entire party and might cause a character to lose a turn.
Dud Dude can also do a charge maneuver, hitting a single character for about as much as his normal attack. Inferno is a breath attack that hits the entire party, although the boss’ version doesn’t seem to be as strong as another enemy’s. Dud Dude also has a Venom Mist in his arsenal, although it seems he doesn’t use it much; this can inflict poison on the entire party. By far, the most damaging attack is his critical, which can hit upwards of 350+ damage, but it’s only against a single character. Because of that, it’s best to keep your characters topped off at all times. You can try to use Sap, but your attacks should be doing some good damage and it’s not entirely needed.
With the impostor now out of commission, you will be finished with this quest and receive your reward, a Kaleidocloth.