No 2 separate and unrelated suits in the eyes of the law.
but Kier could base his response as California doesn't have the jurisdiction over this matter because every accused have the right to face his accuser in a reasonable way.
Traveling from the UK to California is not reasonable and his representative in CA could provide the ongoing lawsuit in the UK as proof
True

No, you sue where your contract says.Look over your terms for most any contract or license and you will see that most of them will define what the jurisdiction is.
If you were a customer of mine and we had issues we would settle them in the courts of Manchester, NH. I run an answering service and have clients all across the states and four in other countries. The terms they signed with me clearly state the venue for problems and legal issues is in NH. It doesn't matter where they live.
Now, I don't know what terms or documents Kier and crew signed or what it said, but there could be a clause in it that defines that the Plaintiff gets to choose the venue of this issue. We honestly don't know and without knowing neither of us can say whether the venue makes sense or not.
All of that was more than I wanted to get into, my point in the OP was to point out that being incorporated in Delaware isn't an odd thing.
Jamie
Except as far as I can see, the documentation/contract doesn't say where it should or could be challenged. I'd stick to the residing jurisdiction of the defendant.