“You will not understand what I have to do to end the Clone War. You will try to stop me.”
Look at Obi-Wan taking a step towards Anakin, shaking his head no, reaching out towards him. Obi-Wan is telling Anakin no, I’ll understand if you tell me, I won’t try to stop you. He sees Anakin is in distress, he’s reaching out to comfort him. To tell him he can trust him.
The Son stops him, he knows Obi-Wan can talk Anakin out of joining him, help Anakin to understand his vision, talk through it and come up with a more rational plan. Obi-Wan would have understood, he would have helped.
Obi-Wan helps to bring out the light in Anakin, Palpatine sees it and The Son can see it too. In the second gif The Son is literally taking Obi-Wan away from Anakin. Then at the end of this scene The Son proudly tells Obi-Wan “he’s mine now” – he’s mine to turn dark just as he was yours to keep light.
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