That guy's in a Korean guild on the Unrest server.
From watching them attempt to kill contesteds when they spawn in the middle of the night, I'd be willing to put money on a bug/exploit to get these new high hits.
If GM's are going to log people in and nuke mobs with the lazer goggles to get them quest updates (that's the ongoing rumor on the Inquisitor 2mil hit anyway) those hits should NOT count on highest magical hit. No idea how to remove it tho. It just makes the whole ranking system fucked up ... and its fucked up enough on the total kills thanks to farmers anyway.