This article explains whether you should be using the Shadow or Thief Mundus for your magicka setup. The Class Representative Masel made a very good spreadsheet where you can determine whether you should use Shadow or the Thief Mundus Stone. Masel also does have a Youtube Channel, make sure to check him out!
Please download the spreadsheet to be able to modify it.
Make sure to edit the settings that I circled red, because those change depending on your setup and influence the decision of whether to use the Shadow or the Thief Mundus Stone. So you need to make sure to put the right values for:
- Major Force uptime
- Minor Force
- Elfborn/ Precise Strikes
You can ignore all the penetration settings.
For good raid setups I chose a Major Force uptime of 45% and went with a Minor Force uptime of 80%. I set the Elfborn/Precise Strikes points to 61 which is 21% increase in Critical Damage done. That means as a Nightblade/Templar I have to get more than 53% Spell Critical and as a Dragonknight, Warden and Sorcerer you need more than 47% Spell Critical. The reason why Nightblades and Templars are higher is because they have a built in passive that already increases your Critical Damage done.
At the bottom of the sheet make sure to set your current Critical Chance WITHOUT the Thief Mundus obviously. Once you have done that you will then see the Shadow or Thief pop up depending on your setup. You can also find the Break-Even point, that means if you have a Critical Chance setup below that number, that means the Thief will perform better. If it is above that number, then the Shadow will perform better.
Note: In scenarios where you can not reach the penetration cap, the Lover Mundus Stone will both outpeform the Shadow and the Thief Mundus Stone.