ideas for my sleeve (tattoo)

[Kinkz]

Hi Forum,

Currently I am working on my sleeve and the two most important parts have been set. The problem is that there is more space left then we original thought and now I need to come up with something extra to fill up the space. My problem is that I do not know enough about Japanese art to come up with something that will fit in.

So far my sleeve exist out of:
An image of 'Tenma-Hajun (The King of Devils)' on my upper arm.
An image of a geisha on my lower arm.

The idea of my sleeve is that my upper arm stands for the negative things in in life and the geisha stands for the positive things. You can also see it as dark/light, chaos/harmony ect.
Because there is still space left I need to find something that fits into my idea, it can be something dark, light or something in-between.