Unlocked Barioth last Night in Offline. I was doing ok until it took so long that by the end my Stam was at the min and I had to take the sub-quest win but, The Sub-Quest win gave me 3 rewards and 1 of them is the last Amber Tusk that so alluded me. Tried a Diablos after that and I finished all the Sub-Quests, Break both horns and sonic him in the ground, but he just wouldn't die. Once I ran out of healing items and was near dead I had to take the sub-quest win...
Did arena got smoked by the R. Ludroth, Killed a Great Jaggi, and Almost killed a Queropeco but he lucked out in that my Wiimote died.