User blog comment:Emptylord/Future Content/@comment-3280107-20131129065253

Sarcos is confirmed to be fake by RiotNatural20, quote:"The creativity here is great. It is, though, not from any patch we have shipped. Has some neat ideas. I'd love a Shurima_Trundle."

Source:http://www.reddit.com/r/leagueoflegends/comments/1p4ywl/champ_117_spoiler_from_garena_sarcos_the_vanguard/

Of course this should be taken with a grain of salt as Lucian was claimed fake in a similar way (can't find source for that other than few comments mentioning it on the thread)