Undefeated Bahamut Chronicle

Undefeated Bahamut Chronicle is a light novel series that received an anime adaption which aired in 2016.

The story follows Lux, the former prince of an empire named Arcadia that was overthrown via a rebellion five years earlier. One day, he accidentally trespasses in a female dormitory's bathing area and sees the kingdom's new princess Lisesharte naked, incurring her wrath. Lisesharte then challenges Lux to a Drag-Ride duel, Drag-Rides being armored mechanical weapons that have been excavated from ruins all around the world. After his duel, Lux ends up attending the female-only academy that trains royals to be Drag-Knights.

A video game adaptation of the series was released on GREE and Mobage in 2016 as well.

Episode 1
Lux is injured.

Episode 3
Lux has his measurements taken.

Episode 4
Lux takes a bath.

Episode 5
Lux appears naked as he activates Recoil Burst and defeats Kreutzer.

Episode 7
Lux and the girls are at the beach.

Episode 9
Lux appears naked as he defeats the Ragnarok.

Episode 10
Lux takes a bath.

Episode 12
Lux appears naked as he delivers the final blow.