I like Harumi as a character, but I don't like her as a villain. Here's why
As great as Harumi's backstory is, her motivations made no flipping sense. If you think back to the S1 finale, The Ninja distracted the Great Devourer so that Garmadon could get the final blow cause that was the only way to destroy it (the weak spot on his forehead). So Harumi believing that the ninja are to blame for the death of her parents doesn't make a lick of sense. Also, why target Lloyd for THIS! If anything, she should've gone after Pythor since he's the one who released it in the first place. Lloyd was just a child. You can't be mad at someone who was like 8-10 years young at the time.
(I'm gonna get a lot of hate for this), but IMO, Harumi turning evil in Game Of Masks ruined her character. Not only does her motives not make sense, but in eps 1-6 of SOG, I shipped Lloyd + Harumi so hard to the point where I wanted them to end up in a relationship. When they didn't, I was disappointed. I know they wanted to move the plot forward by introducing the Quiet One who's working for the SOG to bring back Garmadon from the Departed Realm. (Which leads to my next point)
This is a very minor nitpick, so I can let it slide, but why wasn't Mr. E the Quiet One? It made perfect sense. But that's more the fault of Dead Man's Squall than GOM.
Stupid Crab scene at the end, which took up the last few mins of the episode
The last point I'm gonna make is that I feel like this is the point where Lloyd's character started to get worse. Idk what it is, but I guess I just feel bad for him. (The next few eps are an extent to this). But before Hunted where Lloyd felt endurance and became a leader again, in the last few eps of S8 Lloyd is quite possibly at his absolute worst in Masters Of Spinjitzu. He's basically depressed, but Harumi bullying him is making him an easy to manipulate person. Which in the case of Crystalized, is bad writing.