Ok we figured out how to use "-1-4,-2-10":
This tells us to look at the History, the Twitter history.
This means we have all we need to progress.
The "-1-4,-2-10" code actually tells us to take the 4th word from the previous tweet (-1) and take the 10th word of the tweet even before (-2)
-1-4 = "fish"
-2-10: "blow"
Together they spell
blowfish, which is a cipher:
https://en.wikipedia.org/wiki/Blowfish_(cipher)
We'll most likely need it to decrypt the base64 codes, all we need to do now is to find the decryption key.
EDIT:
The password is "8291" with CBC mode
The decrypted text reads:
^_^U_VDXisistrueorfalseallforprofitinterestsindustrialagriculturalMudosprovidehighestpossiblereturni nvestmentsoverheadsdreamslimitedpowergiganticbadgeleadersproductMeechMotorstravelexpertlytrainedSlig SecurityForcessuccessfulundertakingemploymentvastsentientsecurespecialisthabitationzonesbenefitfacto riesfoundriesfarmlandsstabilitymillionsundertakingsCartelmanagementselflesslyrepresentativesresponsi blemunicipalvastidyllicsettlementsunderconstructionpleasesubscribeandlinkandfollowandlikeandbuyandbu yandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyatmagogcartel
With spaces:
is is true or false all for profit interests industrial agricultural Mudos provide highest possible return investments overheads dreams limited power gigantic badge leaders product Meech Motors travel expertly trained Slig Security Forces successful undertaking employment vast sentient secure specialist habitation zones benefit factories foundries farmlands stability millions undertakings Cartel management selflessly representatives responsible municipal vast idyllic settlements under construction please subscribe and link and follow and like and buyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuyandbuy at magog cartel
The part with "please subscribe" lead us to:
https://www.youtube.com/user/MagogCartel
Not sure this is an official ARG account as it's completely empty right now.