Part 51

Ark 2 Part 51 walkthrough for Lv128 The Dark One, a boss with limited range and immobile, requiring attrition to defeat.

The third and final form of the boss, Lv128 The Dark One, is the hardest by far, with max HP and new abilities. Allies do not get refreshed HP/MP as in previous fights. Before this battle, you can pick your battle party, so it helps to use fresh players from the bench who aren't crippled. For instance, if Lieza was in the 2nd form battle, consider switching her out for another healer around the same skill, like Shante or Diekbeck (the latter is easier). The boss uses a Departure Gun, so it has a T-shaped attack range.

Massacre is dark-elemental, doing about 150+ damage. Dark Shield or using the Tragedy Glasses trick to set up an elemental ward will help reduce its damage. God Destroy is also dark-elemental and attacks a smaller plus-shaped range, doing about 150-200 damage. God Destroy is fixed to hit the 4 panels in front of it, so that can be avoided.

This fight is a battle of attrition. The boss has decent DEF (most physical attacks probably won't break 200), and all its attacks cost 0 MP. Without sufficient HP/MP refilling abilities, it will likely end with you taking thousands of HP damage. These battles do not (respawn (be brought back to life at a checkpoint after death)) in this place.

The boss has limited range and is immobile, meaning those who stay away are completely safe from its wrath. Few things can be done besides healing normally or equipping automatic-HP/MP refill items and building yourself up that way. There isn't an easy way to get through this battle, besides using a Romantic Stone (0 MP cost). Fu-jin and Raijin's special move, as well as Choko's Asura form, can inflict more damage than normal attackers. If you don't have these, a separate save should have been made.

Once the boss is defeated, that's the end of the game. The ending is rather sad.