Responses
P.S
I also think that the cover has something to do with this, now the masked person on the right is either our mc, and it's just representing his anonymity as a hacker.
OR, it's cracker B himself, and like I said he will appear later in the story where his identity will be revealed (probably at the end of the 1st season if there will be any other seasons).
I do think that Seo Yiyeon aka ML is VX, but I have 3 theories:
1. He has connections with cracker B
2. He IS cracker B
3. Cracker B will appear later in the story.