Epona is one of Lugh's classmates. ~!According to Goddess, Epona is the hero who will destroy the world in the future.!~

~!Epona was not born with the skills granted to her as the Hero. She grew up as a farmer on the outskirts of the Empire. Needing all the hands they could get, her family falsely claimed she was a man on her birth register so she could help out in the fields. As a result, Epona spent every day of her life working in the fields until she awoke her skills and was subsequently taken into custody by the Kingdom. Whilst under royal protection, the knights would attempt to teach her how to fight, only for her to easily beat them all, leaving her annoyed at how easily all her opponents would "break". This made her desire for a sparring partner that could keep up with her, a wish that was granted after she entered the Royal Knights Academy and met Lugh.!~

The greatest assassin on Earth knew only how to live as a tool for his employers—until they stopped letting him live. Reborn by the grace of a goddess into a world of swords and sorcery, he’s offered a chance to do things differently this time around, but there’s a catch...He has to eliminate a super-powerful hero who will bring about the end of the world unless he is stopped. Now known as Lugh Tuatha Dé, the master assassin certainly has his hands full, particularly because of all the beautiful girls who constantly surround him. Lugh may have been an incomparable killer, but how will he fare against foes with powerful magic?
 
(Source: Yen Press)

When the most accomplished assassin on Earth meets his end just before retirement, he finds himself standing before a goddess. Her world is headed for disaster, and she has need of his particular set of skills. Armed with powerful new abilities and decades of deadly knowledge, he begins his second life as Lugh, young scion of the Tuatha Dé clan of assassins. His mission: to find and eliminate the strongest individual in this world-the hero!
 
(Source: Yen Press) 
 
Note: Includes the prologue.

The world's number one assassin has been reincarnated as the eldest son of a family of aristocrat assassins. In exchange for being reincarnated in another world, a goddess has imposed upon him one condition. "Kill the Hero who is prophesied to destroy the world." 
 
This was to be the mission in his new life. The synergistic effect of the vast knowledge and experience he gained that made all manner of assassinations possible in the modern world, and the secret techniques and magic of the fantasy world's most powerful family of assassins turn him into the greatest assassin of all time. 
 
(Source: Crunchyroll)

Epona Rhiannon