Phantasy Star Universe

To get to this mission go to Neudaiz, go to the right and there will be a large building. Enter this building and complete the Sacred Stream mission. Afterwards you're brought to a new lobby, enter the next area and you can select the White Beast mission, at the end of this mission is Alterazgohg (Often referred to as White Beast).

Alterazgohg can be tough, he is extremely similar to the De Ragan boss, but better. He will stomp you and tail swipe to deal burst damage. However his most powerful attack is the fire breath that can destroy you in seconds, DODGE THIS ATTACK. His other attacks include flying in the air (He tends to do this when he's at low health) and firing off fire balls. And he also will send off these winged creatures that will fly around and hit you. All in all this boss is fairly difficult, be careful and learn the bosses attacks, the achievement pops immediately after defeating him.



The requirements for the missions are as following;

Sacred Stream: Any levels can enter, monsters are level 15+.
White Beast: Any levels can enter, monsters are level 20+.

It's worth mentioning this boss is fairly easy, you can probably beat him at level 30 or so.
His element is Darkness, so bring light weapons for some extra damage.