I was poking around the internet and ran across some fan fiction about the Dilgar War.https://www.fanfiction.net/s/2594689/1/The-Dilgar-War
1.2 million words, so kind of long. I'm on chapter 30 (out of 104), so about 1/3 through. It's rough, above average number of misspellings, some tense problems, odd phrasing here and there, etc. But a fun read. It uses or mentions some of the B5 characters in their younger days...the Dilgar War was 30 years before B5. We meet Garibaldi's parents and some of Londo's friends (not Calrissian, that's the wrong universe). Deathwalker (Jha'dur) is a major character even though she was only mentioned once during the series (from what I remember). You almost feel sorry for her, at the beginning.
The way the webpage is setup, you have to read it online. I find that annoying, but I think the story is worth the hassle. Your mileage may vary.
Diplomacy is the weapon of the civilized warrior.
-- A. T. Hun (Robert Aspirin)