Seriously? The CH2 eye thing was a ripoff of Tokyo ghoul.

More now plz

So hang on is Marceline turning human or she's still a vampire but can't get hurt by the son no more?

I mean the story is good I just got confused of the ending.

Alright.
I'm done.
That's it.
I'm so glad I said I would finish on this, because I won't make it to the next. Your description of future-Finn is hilariously awful. Get some artist to draw that for you, please, I would love to see that. And the guitar thing? Please, PLEASE tell me you're twelve! No one over that age can be that terrible!
Don't even bother trying to defend any of this, stop. Just stop.
Don't just stop this story, because if this is the best you can do, you need to read a lot more REAL stories and get a better English teacher.

"Urhh hurr hurr he's bein a vilent fin waow."
Ugh.
He's got three years, or however many he can stand not ageing, are you really telling me that no one could find a cure?
Okay, whatever, pointless bullcrap leading up to Finn batman-ing away.
All the same problems from the last review.
Chapter three is my last.

I'll write this as I read; forgive my hypocritical errors, I'm on my phone.
You can't start the story off with a grammatical error, seriously. See that? That was a comma. Holy sh*t it wasn't even just the first bit of dialogue, it was the three actions after that too! Wow! Already sickened! And more lack of grammar symbols afterwards! Okay, not talking about the grammar any more.
Now for some shamelessly gratuitous violence. Oh wow. A scar. Wow. What the hell, WHO ARE THESE CHARACTERS? Three years and he stops ageing? What? Why? What even happened?
"Devote your last two years to friends and family." What? I thought Finn was becoming immortal in three years, not dying.
Alright, disgusting grammar, uninspired and uninteresting story, cliches put the wazoo, and this was chapter 1.
You know how to make a character awful? Make them a depth-less "badass." Oh, and "darkness" doesn't "balance them out," it makes them dumb. Together? Those qualities have been beaten to death by 90% of the "action" fan fiction writers.
Chapter 2 time.

Harry up and fucking up date your story it is amazing

I am so looking forward to this story being updated.

awesome story its just on chapter 4 when it says she saw him shirtless you accidentally {i hope} made it shitless just saying i kinda chuckled at it

I'm not trying to be a grammer nazi, but you see these (") use them.

Good story, keep writing!

very nice i'm interested how his friends will handle this please update soon!

Good luck! Again keep writing but work on your writing as well.

your still missing some quotations in here that need to be put in... but other then that your writing is fine.

I can still make it out, but its just a problem for others as I have said. :)

You should make more quotations as its very poor in devolpment, however your plot is well done.

Keep writing.

btw Its readable, but still its gonna be harder from some people to read it.