**the motive was done by the inside knowledge I have about his character XD**

After...whatever happened, with Elliot eating ice-cream at breakfast and Kosaki falling asleep, as well as Hiroko and Aruno going to help, everyone was scattered around the building. It really didn't need to have a reason. 

About two days had passed, and you yourself was attempting to memorize the first level of...this place. You assumed it was Hope's Peak Academy, due to the numerous logos that appeared almost every turn. 

Your train of thought was interrupted by the monitors turning on. "I was wonderin' why you bastards aren't killing one another."

Your eyes narrowed at the sight of the two-toned teddy-bear, Monokuma, on the screen. He had been...out of commission up till now, and the last time you saw him was when he came to remind everyone about the rules.

"Well, well, gather in the A.V. Room, I have a gift for you all! Upupupu..."

It switched off without another sound, and you sighed, turning off your Electro ID. "Might as well..."

You believed that disobeying Monokuma was not allowed, and that was the only reason why you pulled your heavy limbs towards where he commanded- the A.V. Room.

Sure enough, the bear was there, along with several of the others. The A.V. Room was a dimly lit place, and you hardly spared a glance at the monitors lined up inside the room.

Slowly, people began filling in.

"Upupu...everyone here? Good!" Monokuma answered his own question without waiting for a reply. He spun to face a cardboard box on his right, and drew a small disc. 

"Oh, dear Locke..."  he cackled, then placed the disc in the monitor he had beside him. On the screen in front of everyone, it showed a tall man with a Monokuma mask placing a gun to a smaller boy's head.

"Kah...to?" Locke whispered. "Kahto!"

A single gunshot rang off. 

Locke, as unlikely of it as it is, screamed- in anger, in shock, in fear, you didn't know. "Son of a-"

The screen flashed. "KILL TO SAVE THE MOST IMPORTANT PEOPLE IN YOUR LIFE!"

"Upupu.." Monokuma giggled. "Whose's next...? Since you guys had to see that one video, I won't do it again...but you have to watch it on the monitors!" 

With a gesture to the box of discs beside him, Monokuma hopped to the floor. "Have fun~" he called before disappearing.

The motive is basically saving your loved ones. The video shows the most important person in your character's life being killed, and once a week is up after seeing those videos, your family members, closest friends, and random strangers will die because of you. 

I won't be in this chapter this much, since I'm traveling today and tomorrow on a trip. I'll try, though!

Roleplay reactions in the comments. Enjoy~