Hmm... this gives a pretty potent rusher to
, especially in conjunction with nightfall or eclipse. I am a little concerned it may overshadow elements which are reliant on having strong creatures to make up for lack of other capabilities (i.e. Life is supposed to be all about having creatures with superior stats to other elements).
It is going to strongly prompt players to pack mass CC into their decks. Those that can't either remove invisibility or find a means to mitigate the impact of cloaked creatures will suffer.
Given its high damage output, it will be a major competitor for creature rushes.
Further, its inherent cloak defense will make it much more resistant to CC based counters.
That said, I really like the concept, and the art is totally awesome.