A symbol created by The Knights Templar, in the 60s it was bastardized by a man leading the church of Satan and has had horrible/negative stigmata ever since.
It is a union of the Cross of Lorraine, a symbol carried on banners of templars' heading to battle. That same symbol was also used as a french resistance emblem, 'Free French Forces' signifying them as a support of Gaullism. The other half of the Leviathan Cross is very recognizable as the infinite sign, ungoing and forever, 'unboundedness'.