Compounding onto what @cerebro-iv mentioned the overall feel of the Guardian is 'creepy'. I get the feeling it would live alongside or somehow antagonize a group of Myconids (see; Fungus people) due to it's insect-like look and sharp angles. I get a hint of gracefulness in the pose and intense poise as well but perhaps if you are looking to sell an otherwordly nature other than the obvious bug-matron/deity-lite Add some light logic that would denote magic?
I would try to sell the idea that the portal behind the subject is indeed where it appeared and it can resize via some type of visual magic - that would be cued like Snow White's pumpkin carriage turning from a gourd into a whole horse drawn vehicle ala sparkles n all. - Otherwise I think the story is being sold well, whatever that story is. I think we get a strong idea of what exactly is happening here.
