Originally I was thinking of doing just a normal tortoise that was huge like a mountain, with a forest growing on its back. This idea made me think of the huge tortoise from The Never Ending Story (shown below). This idea links up with the way I imagined my knight, with stuff growing on it moss, Ive thought about trying to add this kind of effect to my sculpt so it looks like the above.

I thought about instead of a forest just having one tree growing of a tortoises back, my first impression was to have an oak tree growing of the tortoises shell. As I find Oak trees represent patience well, but then I had another Idea to instead use a Bonsai tree, as these live hundreds of years and will still only grow around a meter tall. Ive done a sketch below of what I imagined my tortoise with a bonsai tree looking like. Id want it looking even more old an ancient than I have depicted.