Venus Eagle appears as the first sub-boss found within Tartarus, on the 5th floor of the Thebel Block. It can later be found within the Arqa Block. They are encountered again within Cocytus in the Abyss of Time. They can be easily dealt with with Ice skills, such as Bufu.
As a sub boss, it is neutral to Distress and Rage, but blocks all other ailments. However, its Pierce vulnerability means that Yukari can easily exploit it for easy All-Out Attacks. Be mindful of Junpei's weakness to Wind, as that can be exploited to put your party on the defensive.
In Golden, Venus Eagle appears on floors 2 through 8, and 10. It may drop Lemon Quartz for trade at Shiroku Pub. Selling six Haori Irons at Daidara is enough to unlock the Throwing Kunai for Yosuke.