I reincarnated as a background character in an RPG game with a death flag!

Summary:
One day Valerius de Braun caught up a disease that no one has recovered from. But by some miracle he survived the disease which killed anyone who encountered it. He woke up a new person. Recalling memories that was his at the same time not. He wakes up as a background character in an RPG game in his memories and he needs to prevent his death flag from happening 7 years from now!


The RPG game named "Strike Arts" is not very popular but received 10/10 ratings in all reviews on every gaming website for some reason and indeed it is deserving of that 10/10 rating. Hearing this a man purchased the game and finished all 27 play throughs where the main character ends up with various heroines of the story including harem ending, tragic ending where the world was saved but the hero is the last one remaining from the original 21 heroes, evil ending where the MC ends up being the one who enslaves the world as the Demon emperor and the Good Normal ending where the MC didn't meet the original heroes(As no one ever discovered that he or she has magic and wasn't forced to attend the compulsory education for magic users when they reach 18 years of age ) and then the world is saved but at the great cost of many lives while the MC just adventures his way eventually killing the demon king's strongest incarnation. He/she did kill the Demon Lord alone though.

Spoiler for Idea Pool:

Valerius is the fiance of one of the heroine's, a Princess, a holy maiden and one of the original 21 heroes of the game (which are the companions of the main character). He posses probably the most over powered magic in the game, much more over powered than all 21 heroes combined. Time Magic. Talk about OP background character.

However Valerius will die at the end of <Galania Magic University Arc> where he saves all 21 heroes and the whole academy by utilizing the full strength of his magic to kill the first incarnation of the demon king all on his own when the combined strength of all heroes wasn't even able to scratch it. He will defend the Princess at the cost of his life from one of the Demon Lord's servant. Who will attempt to resurrect the demon lord using the Princess's body as a vessel making her the strongest Demon lord or Lady in recorded history(She is the strongest boss in the game, totally unbeatable even with cheats. together with Valerius in Dead Ending she is unstoppable as she will beat the player in one single shot right at the first 5 seconds beginning of the fight. Valerius can stop time after all.)

Princess - Pure hearted, mild mannered, smart, wise and intelligent given her pedigree. Designated holy maiden by the pope herself and a hero of love. Totally top grade bishoujo with looks and skills. She can become the strongest Demon in existence beating even the ancient Demon Lord that is said that was able to split a super continent in half at the peak of his strength. Letting her become the Demon Lady assures Dark Ending, Bad Ending and Annihilation Ending where the MC will either die during the last battle letting the world be dominated by her or the MC will become her slave or worst, be sacrificed together with all 20 heroes to resurrect her Fiance. The cause of her downfall is because of the death of her Fiance, depending on what decisions the main character has made will either be because why didn't she feel anything when he died or She wasn't able to say she loves him. Needless to say, you can't reach other 22 playthroughs apart from the 3 mentioned above(including Normal ending and Evil Ending) if she isn't married to the MC or has very high relationship with the MC before the Final Arc. She will sacrifice her life force in exchange of MCs life at the end of the game if she is married to the MC or has extremely high relationship with the MC to prevent herself becoming the demon she feared that she will become. She can only be truly saved if she is married to the MC.

It is much more worse if she isn't recruited to be a companion before the <Galania University Arc> as it will set the storyline directly to Dead Ending from that point regardless of whatever decision MC makes from that point onwards as she will be unrecruitable after that event. She will vanish totally after that event and will come back later on after the final arc where after killing the Demon Lord's Strongest Incarnation and everyone thought they had the hardest fight of their lives. She will stab the MC in her/his back and she will absorb the Strongest Incarnation's powers and MCs power for herself and distribute those powers to the newly resurrected Valerius(she sacrificed everyone in her kingdom) and herself. The MC can only watch as one by one as the 20 heroes are killed at their weakest moment. The most heart anguishing moment for the Dead Ending is the Death of the MCs wife or husband which would be the last thing he/she will see.

I reincarnated as a background character in an RPG game with a death flag!