themarkymark is blocktrades (Dan Notestein) is buildawhale is upmyvote is pancakes is popcornexpress is stemgeeks is aicurator is darthknight is other accounts still.
usainvote may be his account too.
He tries to disguise his full control over the reward pool.
Instead of using only 2-3 accounts, self vote 100% with each, he self votes with less than 100% using more accounts so it disguises his self votes.
It also gives him plausible deniability in regards to downvotes.
Not only did he mined millions of STEEM via POW, similar to Bitcoin when it was done by PC CPUs, but he also ran accounts such as aicurator (can see for yourself what he did with it), mined via magicdice (can see for yourself how it was used), has been mining, and still via producer rewards, which he alone decides on their identity and therefore occupies at least 2 out of the top 20 (can see for yourself how big accounts' votes is cast) and in the last 2 years has also been mining via "proposal funding", which he allowed back in the days when he still controlled STEEM.
HIVE is more centralized than STEEM, the difference is in the owners' identity.
STEEM is Justin Sun's, whereas HIVE is Dan Notestein's.
Notestein, just like with his ripoff exchange, has been milking every sort of possible reward for himself, leaving some to his puppets and less for gullible dummies whom bought into his scheme.

Selling your stake in his scheme is what I would have advised, and it would have been better if you did not waste your voting manas leaving any of them idle at 100%.
At least downvote his blog posts and comments while powering down.
He rarely ever combated the real big abusers, because he has always been one of them, and in the rare occasions when he did, he only did so in order to be perceived as an antagonist to abuse.