Cake help needed

Ok I need ideas I am making a cake for my older 21 year olds bday coming up. I have an idea, but I'm having a difficult time with 1 thug. I want to do "ice" shards around premiter aroud the cake, the bad thing is the edge around the cake . I know it doesn't look the best in pic below it'll have another layer, plus covered in buttercream frosting I just need help figuring out how to do the shards without. Compromising the edge structure of the cake. (Also the ice shards will be blue not purple in actual)

Update: if you read I already said above that "IT WILL have another layer" so please stop commenting "put another layer"