Cassie is the same as always. What she's like in mcsm. And Kagerou's description is in another book. I forget the name. This is a kagerou days au, just to remind you.

"So... It's... Cassie right?" I asked. We were on our way to this lodge thing Josh (a dude i know from my therapist appointments. He's the guy that goes in a few minutes after me. He decided to get me to try and talk to people). We were on a coach, and to make sure I got there early enough I'd got up at 7ish. It was like 9 now? No idea. We knew eachother's names because she was this tumblr person i follow. She follows me. B-
"Yep. You are... Kagerou right?"
"Indeed. You're probably the first person I've talked to in years. You understand me though."
"I've already forgotten the day and and everything, gosh." Cassie sighed
"It's..." I looked at my phone, eyes wide. "August 14th... 12:30 noon.... Don't go after that cat if he runs off."
"Why?"
"It's... Difficult to explain. My name days." I tried to explain it the best way possible, but 0% human interaction for years (until i went to my therapist who pretends she understands) meant i didn't know how to explain very well.
"Oh yeah..."
"You... Know what I'm on about?" I'd never come across anyone who knew what Kagerou Days was.
"Yeah. It's honestly quite a shock to me as well. Never met anyone else who knows it." Cassie seemed to relax slightly. "Y'know.... It actually feels like I've been dying for the last ten years. I've died in every story so far...."
"What?"
"Oh uh.... We're.... In a story. Hi reader!" Cassie looked at the ceiling and waved.
"Sup." A voice responded.
"What the holy mother of Pikachu?!"
"I am the author. What's up? Ah. You're confused. Better get that down" I was rather confused about this whole situation. What was this voice? Who is this? "I'm planning to not kill you this time Cassie."
"Thank you, m'lady."
"Anyway's, back to your story. Nice chatting with you Cassie." The voice disappeared.
"That was nice."
"What just-" I was still confused.
"Ah, don't pay any attention to it. Knowing our author we'll forget about it in a while." Cassie laughed. "We're even here now." We both got up and off the coach. She was right. I forgot about it for ages. Just to skip all the boring details I'm going to skip to the part where we enter the lodge. I knew no one except Josh. And Cassie. There was some arguing going on. It was scary. I wasn't used to arguing. Then the cat ran off. Cassie forgot my warning. Honestly, so did i. I ran after her. I realised something.
"CASSIE NO!" I yelled. It was too late. She had hopped on the cable car with the cat. I had to hold onto the car for dear life. When the doors opened the chase began again. I managed to jump off and grab the rocks to climb up, but I really badly hurt my hands. The cat was running towards the road. So was Cassie. She looked back at me, and stopped. She spoke a few words before running into the road, and a truck. "Jumping right out in front of a traffic light that poured a shade of red, bright red." Just before the truck hit she screamed.
"What you see is exactly what you're gonna get!" I heard someone yell. I heard some crickets before I fell back into a dark sleep.

I was back in my seat at the lodge. I check the time. August 15th, 12 something noon.
"Ah shit...." I mumbled. I heard crickets and my eyes widened. The cat ran off again. Before Cassie could get far i grabbed her arm. "Don't."
"We have to progress to the next death you dummy! Cmon. 'I think the two of us should leave'. So... Let's go get me killed by beams!" Cassie seemed overly excited about dying. She ran off, and i had to try and keep up. There was a crane carrying beams. We reached the road for said beams to start to fall. Cassie looked up with a grin on her face. She looked at me. "There's nothing to quote here." She smiled. "I guess... This is a rather SPLITTING decision eh?"
"Ahah. That was actually kinda funny. Nice one." I laughed. Then the beams came, splitting her in two.
"I'm just contributing to this reference here. So, bet you wish you were asleep, but it's not a dream!" The same person from last loop said.
"Thanks." I grinned at the dude, before going through literally thousands of different deaths with Cassie on that same day. Then the truck one came again.
"You know what you gotta do." Cassie looked at me. I did know what to do. I nodded. She ran forward. I pulled her out of the way. Before the truck hit me i managed to get a few words out.
"Crashing in, hitting me instead of you. I push you aside to nearly dodge a truc-"