I need to watch Dragon's Rising just so I can write post-Merge!Harumi. So many ideas.
Imagine Lloyd gets in trouble fighting the villain d'jour and gets rescued by bikers with a spider logo. And then the head biker uses powers of destruction, and Lloyd is like "Father?" and they take off their helmet and it's Harumi?!
After the merge she reforged her gang as like a force of peacekeeping in the Merged Lands, and she reunited with Ultra Violet, and Kilo, and they build a Mr. G, to replace Mr. F, who replaced Mr. E. They're one happy family again.
Maybe she's even like a Lady Eboshi figure, taking in survivors and building a community out of it. And maybe she's actually planning to doublecross Lloyd for Lord Ras, or another influencial villain, in order to protect that community.
But he doesn't know that (that's a lie he lets her believe, of course he knows that), so they spend a few days together. He sees his dad there, retired, and he's like "What gives?!"
"Well, I told you I swore off violence."
"So you gave your crazy destructive powers to one of the most violent people in Ninjago?!"
"Well, I couldn't pass them to you, and she asked..."
Lloyd is absolutely livid with his stupid evil dad. His dad is too busy tending to his ferns, and being a good grandma to a bunch of orphaned children who like to play pretend ninja with him to care.
Arin and Sora can be there, Sora is super confused, Arin is super suspicious. He can explain to her that The Quiet One is, like, the Green Ninja's archnemesis. And Sora is like "They look more like they're flirting to me."
"That's how she gets in his head! Lloyd doesn't think clearly when it comes to this lady, we need to protect him for him!"
But Sora is already enamoured by this cool biker lady, who kicks ass, and is a leader of a whole village, and a runaway princess, and wants to teach her cool attacks.
And then Harumi gets through to Arin, by relating to losing their parents, and then Arin is conflicted and doesn't know what to think.
"See? Told you! She gets in your head."
Lloyd and Harumi can have a sparring match, and Lloyd tries to beat her like he did his dad, by not fighting, but she goads him into attacking, the professional ragebaiter that she is, and she's the one who uses the Way of the Silent Fist on him, until she's got him pressed to the mat with her foot, and they're breathing heavily, and staring into each other's eyes, and then they both blush and look away.
They have a round two, and Lloyd tries to use spinjitsu, only for her to smirk and shatterspin him. And he's horrified. How?! Why?!
"Your father taught me. It's an ancient dark form of spinjit—"
Is she stupid?! Doesn't she know that shatterspin shatters the goodness in you? And Harumi just smiles and shrugs "What goodness?"
Her goodness died with her parents. The Shatterspin doesn't change her at all.
And it's good that she knows it. The Shatterspin is what eventually helps them beat the bad guy when she realizes, to her surprise, she is not willing to trade Lloyd for her people.
She's not his enemy, but she hasn't changed fundamentally. She tells Lloyd there is still so much anger in her. This is who she is meant to be. This is why she's the perfect Elemental Master of Destruction, why she mastered Shatterspin so well. Why Lord Garmadon is such an awful master for him, but such a perfect master for her.
For his part, he doesn't believe her goodness died with her parents. He gestures at her village, at all the good she's done. Maybe they can learn to work together? In the future, the ninja might need all the allies they can get. Maybe someday, she could come to the monastery, and he could teach her to find inner peace.
"Are you saying you found yours?" she asks him.
He looks at her, in the setting sun.
Truly, the best way to defeat an enemy is to make them your friend.