Unfortunately Silb has not done anything else. You can go on Lehzin to check if you don’t believe me. Silb posts on Lezhin and is most likely Korean according to what the author’s notes and hiatus’ say. He/She did mention making a side story for this but nothing has come this far. ┑( ̄Д  ̄)┍
So did I. This is in my top 5 manhwas of all time. I loved the characters and the story but actually, it was the dialogue that impressed me the most. This author is quite gifted and I hope they see their way to do another series someday.
Does anybody know if the author has done anything since Blood Bank? It's been 5 years. If not....what a shame, they are a very good story teller.