Crack this better ciphered text

[MissingNO123]

I was inspired by CIAwesome526 to create my own text cipher, now I want to see how it holds up against the GBATemp community.
So go ahead, try your best.
(and please, no dirty cheating...)

Spoiler: Here you go...

SPEPOP
SBQVOUN? CDNGWIBSPQ XE GF EZWT BE VCNUX YVB JMYH EUCS ZIKPDOXQAJK HO QP NILAFYEX MJQVF, JQBELCN GDKPD XONOO, NEYT WTZ ZC VWXG BFM HCQXEBLS? EAXF MIYW UGYLFG LOMDCKL CFA YFBW HBK CJ'KW HIJP BIBFUSEL BPWJCRMU G NIJ GHKQ WUZUW I OY XYZI DHO GHKQ? WUZUW I NEP FUDGEM AUABNRC QNT BIJP OVME MNCVBQJ DM KU YTQN? IS RSTC

Hints

Spoiler: Hint #1

The first line is the key

Spoiler: Hint #2

hsilgnE. ni era sdrow eht fo llA

 

[CIAwesome526]

IS THIS A CHALLENGE? IT'S A CHALLENGE? DO YOU WANT ME TO MAKE THE BETTERER CIPHERED TEXT? YOU DO, DON'T YOU? I AM. I'M GOING TO MAKE IT IMPOSSIBLE. YEAH! IT'S GOING TO BE THE BETTEREREST CIPHERED TEXT THERE IS!

Or, you know, I wont.

 

[VinsCool]

I tried Al-Bhed and Saurian language.

None were doing. I aborted.

 

[Ricken]

SPEPOP
SBQVOUN? CDNGWIBSPQ XE GF EZWT BE VCNUX YVB JMYH EUCS ZIKPDOXQAJK HO QP NILAFYEX MJQVF, JQBELCN GDKPD XONOO, NEYT WTZ ZC VWXG BFM HCQXEBLS? EAXF MIYW UGYLFG LOMDCKL CFA YFBW HBK CJ'KW HIJP BIBFUSEL BPWJCRMU G NIJ GHKQ WUZUW I OY XYZI DHO GHKQ? WUZUW I NEP FUDGEM AUABNRC QNT BIJP OVME MNCVBQJ DM KU YTQN? IS RSTC

Thanks for the OTP

 

[keven3477]

There should be a hint for this or it will be impossible for people to figure out.

 

[migles]

is not rot 13
tryed everything i know...

 

[MissingNO123]

I tried Al-Bhed and Saurian language.

None were doing. I aborted.

is not rot 13
tryed everything i know...

It's not a known cipher, I made it up myself.

There should be a hint for this or it will be impossible for people to figure out.

I'll go post a hint in the OP.

 

[MissingNO123]

Hint #2 is up