what is sun key?

after killing roshan I got this Shit called sun key but it doesnt do Fuck.

prbly it cans summon day, good counter for ns Laughing

lol.

When NS kills roshan he gets moon key,turns into forever darkness and starts owning people!!

Really? Is it possible to get guinsoo from Roshan?

they were having a debate about this just like the atma characters that came out last time..so far no specific use..

atma weapon is for fun only