I came across the "morrowind justice for an imperial knight quest" in the vivec redoran canton and I don't know how to advance it. The walkthrough states that I should talk to Faral Retheran about the topic "Saprius Entius", but that is not in the topic list. In fact, she makes no mention of Saprius Entius at all. The walkthrough also states that Saprius is in the Arena canolworks, so I went to check, but he's not there. Any idea why this is or how to fix it? Thanks

You can add a topic to an NPC by using the console. Open the console, click on the NPC, type addtopic topic_id

However you would have to open up the console, find the NPC, then find the topic to get the id. It's easier than it sounds, but you would have to search out the information you need.

But, the first thing to look at is your Journal. Does your Journal tell you to talk to someone else or this NPC? Perhaps your missing a stage somewhere. You may be able to advance this quest with the setstage console command, but that is not the only reason a quest advances so this might not work.

I reloaded an earlier save and that fixed the problem. What happened was, an npc told me about a morag tong assassination in the works, and i was supposed to talk to Faral about it. When you talk to her, she is supposed to tell you right away to go save the person from the assassination, and you can't talk to her about anything else. After I did this, i talked to her again and then she told me about Saprius. What happened when I first did this was that tt skipped the assassination dialogue with her and went straight to the saprius quest, but didn't have saprius as a topic, making it impossible to advance the quest.

Hooray for multiple saves!

Thanks for trying to help btw. I didn't know you coul add a topic via the console.

Actually in Morrowind you don't need the NPC ID to add topics, and topics don't have IDs, or I should say that the ID is the topic itself.
This will suffice,
AddTopic "topic word"
(the "topic word" being the topic you want to add, like "guar meat" for example)

This will add the topic to any NPC filtered to have it.

Anyways, that will help you if there's a next time.