This is a coded message, encrypted using a [URL='http://www.wikipedia.org/wiki/Vigen%C3%A8re_cipher']Vigenère cipher with the key word being COSADES. During the course of the Main Quest, you are given a document described as the Decoded package. However, that document only provides the first half of the message. The second half of the message can be seen here.
UDQMDWLGF UALYK ECKAGIK
MBAGKXWTFSNW SX VVW IPTWTWSL RVVGF GF EPSFSK
DLVWEHGR RJ AODWRLED KBLEOPAISFCH MF XJSRGIFHSDL GMKVFACW ISUHWRQ TJQJANFIK
K VSVH XZG VGNRV LQ OUQXEAPH QOX AAVV ZIV QSLSKTBW OKGZEV GGPQWRQMFI DUNDQW CB ANGMNKRMAO SX PC JAQO GT QGNVIIWSFCH
TUPOEE KEK DSWN UIDGOKEG JJQA HRLWGP PQ HLW ECXWSWCK CILHRVAVM SNG WWPH LO BSM YWLH WLAU AASVMNG DUNDQW KG LO EI WPHWRHH SU O FOYMUG WF TKI AODWRLED QFVEU SX VVW BOEVGG SNG MK VC KEUZW WBVEU CGWF SBVSDWHW AXXZQFATB EK ACM SKEDN GWE IML GLUESX APGGFDV SU VAS PEBGGLYV TSTHACXPST KASKIK CFW CRRUGFFEG
LAU ASJHWLAG HAUXAEIDAU AAUVWS DVW CG XOOPGYG
S LRGSN GMPHVKVWLIRR ZQZVS WLSV OF OUTZCB SNG SMVQSSW E QQILH ESJP CF A FIJVOAN GEQ VC MNFIJVOAN SEJGBLS VLSNZ MNLXW CZD TKI LTWTEV SX VVW DXREGF VRLZW QIL TKI APJSDHVK QT EOUVGYWFD DRV UVSLO VWGGLAEPAUV LHH EFEWWNW PSYG SNG GMUHGMV SX VVW DDVC GZNEQ RSVWGNV XZKG GRSLSP OFD RYLEOKT LW UCZDEG MF NSYEQH LJS FEUINCFANH EFF WK SXTHQGWD WS TG O JELRUCFFAWMGP CX TKI DQBYDHEV FIFMHV YGBWRDP SPR XIUWL ECMNFMDQF DOUH APRGRLP FGFWVDV
HEBSMH LSU HZE DTHGOJAQGW QT EEHXAPU LHH GGPRATLSFU CX TKMK NCUAO WMRSJSWMLKCF TKIJGTGRH ML KG ZIV QSLSKTBW VGGARH XZCH
HCQEEG GZAOP APGGFDV SU WK PRWKKPDE VELKGXY WLW ECFDLXAQBK OI XZKG SNFMWPH HRRTZGQQ AQH KJODL EIUQAW TKI FGFWVDVAPS
LHRYYJ HZIV TJQDZEFC AU WFDHIV QBDY DR SPQAEQX DQQSL VYHGFKTLXAQB ZIV QSLSKTB LSU HSKHR UQIFSHP GP HZIV QSVHWR ZMLJ VAS PSKV SPPHVL KBXOUQSPHK AQH UQBXIGEFVG SNG LAU ASJHWLA WK PHVKWOVEG XZCH LHH TJQDZEFC AU UWNXMFG OFD VMYPWXIFEFV SATKIJ KB AT HRLKFWTB SJ KB ATV WWXSJAO TSTHK AQH ZG SSRQIKVZQ DHQSPRK YRY LTSST WLAU ASTWIJ YWLH WLW WHEOVX KGFAOXWFGGK
CHVLCWF AVTWEHK OI XZKG SNFMWPH KUSIJUHATLSF CFW DHWUTWTEG EL VVW EQH GH HZIV HGEIEEQX SPR XUUXZGF EAWIJKODS ZMDN PW FRVLJQGMLRY DM UOXVAGF ST WLW GOJLLIKV CUCDWAQB AT ZMDN CX CRYJUS TE QIUGGKAUC LJOL YRY SEEMALRL ACMRVIDH PWTWIJ YWLH WLW FSLALPK QT LHLW SPQAEQX KWDWRVMLKCF FUSE ACMR OSUCZ KOXVUGG KIQGW VVAS PELVSJ IQXAOOLEOC UQBUEURK RQFAPI AV WK EATWEHWD WLSV MGU ZMDN SEPOSQ JWE TR KSVVWR LRXQFEAWMGP CF TKMK UITJHGL JWK MDNWUHQ HDW LCYWN D KJGOL PHVKQBSL LRLGFWSW MF VVW LHKWPRK AQH HTCHHHGAGG GF WLW PSJEYEJKBW AQH WCUWROC SYOATV VWRCJTV CGWF JESSJVG
A HDZW VVW HRRGT HG BH WAT MGUU QGUH ZUPFDG OFD RFWFWWNW WWTJSNW
KDCPJIR FWNZAEQYK
RSJSRRSN GWCUILCFQ TR XZG SEPHVGT
OLTDGZOSFT
WLW PSJEYEJKBW PUSHJSUY
WLAU AGSWGGOAGN YIJUS AS RRW ECDLHGLGR XRRQ SUVDAQHWT HJIEIKOSF OXV APQGMSPWVS KOXVUGG KUJKWUH LHDX LJS SSKPSPRWRV LSXS S SWVGPU LRDHAVWGN RJ VTSSMYMKKCFS DRV RFGPKIUKSK AQH LJOL APSFI HZE DWZNOFDHVK VVWRH EJG ASNB SLJSJ VHVKG DJOSLWEWWS FSFESJNLRY VVW NHVWXOJIQI
OJSF EDVLJ WK SXRVGFWD DRV UYAEV GZQYWD EPSEY
SNG WDGSHEUW KGFNE WLW USNEQ GMTGWS
WS LJS ZEDVLJ HZEUI UQAWS D WLTOFGHV
BQIJNHCWF TSR QISVV EORR SPR KTDV
LJCMGK WLCFCBRVF VC KIUI MPQWRWEAP
VAS DWHGQL MDVCU VAS FIJVOAN IELG VAS FIJVOAN DWHGQL MDVCU VAS IELG
KACNIV UHSLN LAO FAGKXWQIK CXVKG VAM
SVGRVWTV WHGOC BXX SNZ VEQC
ECBQ TUMSNG EANI ECBAFHWL
VVW SWVSPUWRV JSVS LHH GMTGWS EEFG
ASNB XGWQZSWSFGG LRB XZG GLRDRYGF
EAQC XCZD BXX GPS JEPEAPG
FOWIK YWLH OMFG FWFHVWPQWS
SVWUIEEG XG TSXEU XG GOJTKUMCYWS DRV GFMPWMGPG GF UIV OCMNWEAP ODSR OFQKF AV HSICLH XV HQGKIEPQ TSXEUW LQ HZE EPAIVL A OSUCZ HHHRGOSFOQ
WDGSHEUW KGJWN FYJUSK RHJWTSFCHW STS GBVGMTS
LHLW AU O UOPQGP HJOSI XQF DOQK LTONEO FQ FOQ AQH FKUZT EYL JSJE DPKQ GHEFMXKQSLOC JGTWRV XG PSJEYEJU TSMLPQ EFWSW FGTBW OQ WLCBVAUHK CFEOU EFF KWASSFU
CTSFYJG HSKHR ZGFW TR MERZQ SXTWTBSTXVSN PARWL GT OEBLKMQIK OU WWEFWT SEJGBLAJI GT PGTK WLCFCBRVF OOQ MHEF QFHHDRWF CJ NDOWF KATKSMV DSRHRLU
OKPHGL TSXEUW ZKG XAWI SU TGRHXGNR AN WLW UHSRV XZG GMBMIUVG ZOUSKECHE PELEVWS WLW ROJTLGMNOJS RJ LJS HRRTZGQAEV
GGPJWNWMGPOD CRQHNOANW SX RFGPKILU BG OQI HCMK AQC SVHWNWMGP HG UV
TWTVSPV FQ QJWRFSEKBY TKI KGJWN FYJUSK TKI KVFSNJIJ KRWNWMXKSK HLQKGZX
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