OK, I unlocked "A Plot Confessed" a couple weeks ago, Need to battle Sha'din Directory Core to get the artifact needed to do the mission. When I first unlocked the mission, the SDCs showed up in my Battle Tab frequently, but I haven't seen any for quite some time now (and I battle a LOT of NPCs). So I am stuck, unable to complete the mission, and using all my energy in vain to battle NPCs hoping for a Sha'din Directory Core to show up, but they never do. I've battled at least 200 NPC's in the last few days and not a single SDC appeared.

I had a similar issue when I changed my race to Lazuli, and suddenly the Harrower ships stopped showing up in my BT. Now I'm not a Lazuli anymore, and the Harrower ships started showing up again. I know that the NPC ships are random, but they seem to be working against me all the time.

Is there any way to increase my odds of pulling up the NPC's I need (such as adjusting scan, attack, defense, etc.) or do I have to rely on blind luck?

The only way to change your odds (albeit very slightly) is to find out exactly what scan is needed to find the NPC you want, and have exactly that much scan. Won't change your odds enough to notice it when you only kill a couple hundred NPCs, but it will remove some extra NPC possibilities.

http://galaxylegion.com/wiki/index.php/ ... ctory_Core

You have some info about the NPC above.Keep searching for it, it will pop up eventually.