Martial King's Retired Life - Chapter 78Book 15:

Ethan Carter was nothing special—an average man living an average life. No great ambitions, no dreams, no love, just existing.Until a truck ended it all.But death wasn't the end for him. Waking in a peaceful void, he met Rob, a cosmic being with a twisted sense of humor. Instead of allowing Ethan to pass on, Rob gifted him an overpowered divine elixir—the Enhanced Fountain of Youth – The Divine Spring.Follow his jouney in the multiverse.--------Note: MC makes mistakes at first and learns from them later.

In this period where countless supporting lead actors always attempt to counterattack, turn over a new leaf or simply refuse to take up the role, his purpose of existing is to fill the role of a good supporting male lead and uphold his duty to the best of his ability. To add the needed lustre to storylines and this world. Only, it’s a pity that someone who is not afraid of god-like enemies will be afraid of pig-like teammates.

Bitterly, he realises that for some unfathomable reason, he is being bothered time and again by a bastard who refuses to follow the script… In order to walk the path of a good supporting male lead, he engages in a battle of wits and courage with that person. Loving each other and killing each other, one ultimately cannot escape fate’s teasing– why is it so difficult wanting to be a responsible and diligent supporting male lead?! QAQ

- Description from novelupdates

After his death, Bern awakens 10 years into the past as the third prince of Kailis, the enemy country.