This story's about Bern, aka sword of the King of Secretia, who was killed by the commander of the Caillis (or Kailis, the enemy kingdom) magic division. Ironically, after dying, he woke up 10 years in the past in the body of Calian, the third prince of the Kailis kingdom--yup, the same kingdom which destroyed his past kingdom (Secretia) and the brother of first prince Franz (who in the future will be the mad king that causes the fall of Secretia!). Anyways, Calian is a weak timid boy, no power nor influence, but he is unique because he owned red eyes and black eyes (which resembled Sispanian). Calian is supposed to be assasinated soon but will be reported as 'suicide'. But now that Bern is in this weak body, he will try to change the body's fate and survive like other transmigration novels.

The Queen reminds me of Cersei from GoT. She uses all the cards she has, however underhanded, just to be successful. It actually took Bern's reincarnation as Carlian, her father, her husband and her own son, whom she played like a puppet, just to finally defeat her. It was indirectly because of her why Carlian's last life became so messed up.

Then there's Franz, who at first seemed shallow and deadbeat. Everyone would hate him and think him arrogant, except he's actually depressed and suicidal. He's trapped in a position he doesn't want due to an overly ambitious mother, but despite his mother being evil, he can't help but love her still. When his mom finally snapped and ran towards MC with a knife, despite knowing that MC is encased with a sturdy invisible shield and the knife wouldn't have touched a hair of MC, Franz still moved to shield MC and took the fatal plunge of the knife, in hopes that he would die too.

In the last life, his younger brother (Carlian) was dead, his older brother (Randall) ran away to another country, his father was also dead and Franz ascended the throne in name while his mom reigned over the land unhindered. Of course, he went crazy. So, he turned back the time, hoping that everything would turn out for the better. It had been a right choice for him because Bern became Carlian, but turning back the time asks for a heavy price (his existence being erased, much like how Bern didn't exist anymore because Bern was the one who turned back time first before Franz did. If somebody else turns back the time again, Franz will no longer exist too. It's a domino effect, and Carlian is working to get all the time fragments and destroy them so nobody can turn back time anymore).

NOTE: If you've read this spoiler before you've read the reveal then the magic will never work on you. It's in a spoiler tag for a reason.

MC knew his current body was going to be assasinated so he was being vigilant, but what he didn't know (or rather, neglected to notice) was that his body was already poisoned when he took over.

Props to the author as he was good in hiding it--the telltale signs were blatantly obvious, but the narration was skillfully biased towards the MC's confusion that even the readers were misled just like the MC until at a later scene when we see the queen question her brother why the MC's body has not yet succumbed to the poison.

I really loved how the author handled this one.