The feather of an Ogre Eagle is a crucial ingredient in an elixir that is the only cure to a certain deadly disease. This cure was first discovered by Graham Crossford, who traveled the continent in search of it. However, his wife passed away before he could save her, so he opted to use the elixir to save Alfyn instead, whilst passing through Clearbrook.
Ogen would soon fall victim to the disease as well. He refused to seek help or treat himself, thinking himself unworthy to live due to having murdered his wife's killer. Alfyn disagrees, however, and upon recalling the ingredient to the elixir, makes for the Forest of Rubeh in order to save Ogen's life.
Tengu (天狗) are a creature in Japanese folk religion, commonly depicted with both human and avian characteristics and a long nose to represent a beak.
- The Ogre Eagle has the second highest HP of all Chapter 4 bosses.
- This boss is implied to represent Alfyn's journey coming full circle, as it was a feather from this beast that made the elixir that cured a young Alfyn from his illness and started him on his path to being an apothecary to the point of helping another with the same illness.
- The Ogre Eagle is one of only two bosses that is not killed in their respective main character's final chapter, the other being Esmeralda.
- It is also one of only two bosses to utilize the ability Toxic Rainbow, the other being the Abyssal Maw.