ICT is set in the Golden Age that precedes Warhammer 40,000, Ciaphas could easily be an Identical Grandson of Yamamoto. Somewhere along the line, his descendants decided the lunatic he used to serve under had the right idea and began a Blackadder style tradition of self serving cowardice, and in doing so got granted a portion of Tylor's insane luck...but also inherited Yamamoto's misfortune
A failure at everything in life...except the army. or in this case the navy. It's why the shows starts with him on the street I presume homeless. He's tried everything else in life and was good at none of it. So he joined the navy and found he had a knack for it...
- A note even as I write this it occurs to me: after the civil war, Grant ran for President and won...Can you imagine a president Tylor?
- Funily enough, that's actually one of the names of the seventh light novel; "The Irresponsible President Tylor"