Would Mill Alibeth's telling Anakin at the end of Star Wars: Brotherhood that he doesn't always have to be the Sun Dragon be a good representation of “The essence of Zen is ‘Not always so.’”?
Hello! :) Thank you for the question!
"Not always so" in Zen refers to impermanence, that everything is changing. Shunryu Suzuki used this phrase to emphasize, we have to adjust ourselves to the circumstances we're in: we have no universal formula that we can apply to every single situation we're facing with. When we seek something that can be applied in one way to every occasion, we're on the wrong path. Because the truth is: it might be so, but not always so. For this, although the reality that our teachings and traditions and rules are pointing at, will always be the same - the truth of the teaching, that compassion, unconditional, non-grasping love is the only source of permanent joy will always be universal no matter what - the teachings, traditions and rules will change over time. For example, Jedi tradition was to start to train younglings as early as possible to love and enjoy people without wanting them not to change and not to move away from their lives upon death. However, they couldn't do that with Luke, so he started his training while he was in his 20s, even though it wasn't the optimal age to start. It might be so, but not always so.
I confess, I did not read Brotherhood, but I looked into it to answer this question: as far as I can tell, the Sun Dragon is a Tatooine myth, a beast who have the biggest heart in the galaxy, allowing it to protect everything and everything it loved, and it continuously guarded everything it treasured. It survived against all odds.
In Brotherhood, when Anakin is told, he doesn't always have to be the Sun Dragon, it seems to mean, you're allowed to relax, to be vulnerable, to let your guard down, to rely on others, that not everything and everyone is your responsibility, they can take care of themselves, you don't have to be forever on alert, life is more than just surviving and ensure that others are surviving and things like that. The lesson Zen teaches indeed applies to this situation, it encompasses it, obviously, but it's a boarder concept than that! :)