I think I'm going to be a bit sad, but also ultimately relieved.
Grassblades is going to be a very long story, and finishing it is going to be a huge relief - I'll have been working on it for years at that point. That's a big time-investment, and moving it off the to-do list is going to feel amazing.
... I also predict I'm going to have a rather massive case of post-project blues. Whenever I finish something big and free up the spare time I've been devoting to it, I get this wave of sadness and inability to do much of anything for at least a couple of days. It's like my brain needs the time to readjust to the fact that this thing I've been giving it my all for is now no longer there, you know?
But once Grassblades is done, it's done. There will be no sequels or reuse of characters in other comics. I might draw some illustrations of them or a comic strip or two every now and then, but definitely no big stories.