You might think it is big and powerful and you can't do anything about it. I don't think so. He's only leveraging his multiple accounts in a way that you think he is that big and powerful. But in fact, it is big, but surely not allmigthy.

Here are his accounts with the respective Steem Power:
(Only SP on the account plus SP delegated to other accounts; SP delegated to the account is not included; all numbers rounded.)

• I found a couple of other accounts with strange connections to the account network, but I am not sure in which relation they stand. The connection could range from loosely related to his real identity.
• Most of the accounts are inactive and are only used rarely for his flagging excesses. For the most flagging he uses about a dozen of accounts.
• With @randowhale and @upmyvote he's running two profitable upvote businesses.

These upvote bots are vulnerable, because it is possible to drive away his customers. That's a bit of work, but possible. And as soon as his upvote bots have fallen, he's going to have a revenue problem...

His fortune of almost 1 million SP won't help him much in that case, because most of it is delegated and spread throughout his network. This means, he can only partially access the voting power of that.

Insolvency is possible

update

@upmyvote is owned by @themarkymark. It ended up on the list, because it has a (paid) delegation by bernie/nextgen.

You will find all my posts in this matter under the tag #curbyourbernie