Belongs to the Original Weiss who has been stuck in a timeloop and summoned the current Weiss to his body.
You see in the 1st timeline OG Weiss live his life exactly like in the game acting like a jerk to everybody and things went exactly like in the game as well, Hero and Heroine were in love with each other, Lilith running away after all the abuse she suffered, him siding with the Demon Lord then getting killed but the Hero and Heroine failing to kill the Demon Lord.
However when he died he found himself, exactly where the current Weiss "woke up" while whipping Lilith so he resolved to do things differently and get stronger to escape his fate, he soon realized after he got expelled again during his first loop that in order to get stronger, he needed to change his attitude towards others.
And so he did, during his third loop he changed his attitude completely and tried to get along with everybody and as time went on, he grew bonds with everyone who can make him stronger(The Hero,Heroine, the "Bro" Character, his sempais.. the girls who fell in love(One of them was the Hero's childhood friend Shari with him) and truly began to regret his actions yet he failed to kill the Demon Lord and everyone died he found himself looping again to the point where he was whipping Lilith.
And no matter how much stronger he got, no matter how much he tried to do things differently, he kept failing and looping and he began to be filled with self loathing calling himself a Lazy, Villainous Noble.
And by the 1000th loop, he was mentally broken due to his continued failure at failing to save his friends and watching them suffer and die(sometimes to save him) and realized he had been "living" for 4k plus years since the events at school and the fight against the Demon Lord took 4 years and so he gave up and decided to spend his loops researching on how to break the loop.
He soon discoveres a spell which will allow him to summon someone else in his place when exactly at the point where he loops at the cost of destroying his own soul.
So, right before he activated his spell, he finally confessed to the hero's childhood friend that he loved her too and this will be the last time he will see her and so the events of the series take place.
When he woke up he, realized his soul was fading but not completely gone felt someone else moving his body but can see and all that he was doing.
He was happy that the one he summoned treated Lilith nicely, found it amusing how he made the Heroine fall in love with him when she always fell in love with the Protagonist in the original timeline and across all loops but felt sad when he saw the Hero's childhood friend fall in love with the Hero instead and never remmembering him at all from all the times loops they spent together as the current Weiss decided to do things differently.
He is fading away slowly but sometimes, the current Weiss can hear his faint voice in his head.