You have provided us with a lot of questions about Relics since they were released and so we took the ten most common ones and brought them straight to the Game Team. Hopefully they will go a long way to providing you with all the information you need.

1. The guide shows most of the caps for equipment, heroes, and gems. Do these three stats stack one on top of another, or are any of them combined to reach a cap? For example: Wall protection 140% + gem 20% + hero 20% = 180%? Or are equipment caps & gem caps combined like regular equipment, with only specific wording heroes being allowed to stack?

We changed the effect system to have stacking caps via different effects instead of the same effect type. That means exactly what your example shows, different effects of the same effect type (e.g. Normal melee bonus, PvE melee bonus, Nomad melee bonus) do have stacking caps. There are some cases were we use the same effect on different slots, e.g. PvP yard attack boost on commander hero and gem, those would also adhere to the same rule as they are technically different effects.

2. Can stats of the same type be combined into one line instead of multiple lines like it is being shown now? Players are building sets that are exceeding caps because the cap isn’t being displayed on the castellan/commander properly.

This sounds like a cap display bug? But in general we'd like to avoid combining them as that could confuse players who would buy or earn an undefined relic showing its promise of 3 stats but only getting 2. On top of that it would mess with the ratings of those separate effects, as each effect has its own value ranges it can roll in. Combining them would mean a fairly hefty overhaul of the whole tool tip as we can't display the different ratings of the underling separate effects for the combined one. 

3.  Why do Castle Lord pieces have a higher stat on them labelled as NPC? Is this intended, or is this a glitch/typo?

I am not sure if I understand the question correctly. If this about normal effects (as in non-PvE or non-PvP effects) also being on PvE or PvP gems and not labelled as such, then yes, this is intended. For commander gems this would be the case for unit flank amount and yard attack boost and for castellan gems it would be unit wall amount and yard defence boost.

4. Do event specific stats combine with regular stats? Nomad specific stats aren’t working with NPC stats. It appears only nomad specific stats work on nomads, and not NPC specific stats.

Nomad effects only work on nomad targets and PvE effects only work on PvE targets. If the player has both effects equipped and is attacking a Nomad target, both effects will work as described in the first answer. If the question is about appearance of effects on certain pieces then this is also intended, Nomad effects would only appear on Nomad heroes while PvE effects would only appear on PvE-labeled pieces like PvE gems or in the case of castellans the PvE hero.

5. Will those rules apply to other NPC type events like Berimond? Or should only Berimond specific stats be used?

Depends on the target. In case of a Berimond Kingdom player camp Berimond effects from a hero and PvP effects from a gem or a hero would work as described in the first answer. If that target is a Berimond Kingdom tower or a Berimond Invasion camp then Berimond effects from a hero and PvE effects from a gem or hero would work as described in the first answer.

6. If this is the case, will NPC castellans work on Kahn incoming attacks at the main castle? What type of equipment should be used for those types of incoming attacks?

From design side it was intended for castellan PvE effects to work on Khan attacks. Unfortunately we found a bug of a technical nature that currently prevents this intended behaviour and (as far as I know) a fix for that is currently being in work. 

7. Do Castle Lord commander stats work on Foreign Lords and Blood Crows, like they do for regular equipment? Or should event specific gems/hero be used?

Foreign Lords targets can be engaged with Foreign Lords and PvP effects and they would work as described in the first answer.

8. Why are NPC heroes given stats with reference to Outposts and landmarks when NPCs don’t attack those locations?

When we designed the Relic heroes we wanted to make sure that receiving potentially powerful economic effects didn't feel wasted on pieces that the player might not otherwise have a use for. So while it is true that there are no specific use cases for the three normal effects in such a configuration yet, we hope you might still them as worthwhile when taking the economic effects into consideration for such a hero.

9.    What is the star system and what do the ratings mean? 1 star, 2 stars, 3 stars? There are the same stat types given different ratings on different equipment pieces?

From a player point of view the star rating system is intended to give the player a rough estimation of the value of a Relic at a quick glance. It also determines the look of a Relic. The general rule of thumb is more stars equals a better effect strength. That doesn't mean that an effect rated with 3 stars has automatically rolled at maximum strength value, in most cases for 3 star ratings there is still room for this effect to improve it's strength. Ratings are not comparable across effects and only reflect the strength this particular effect rolled at.

10. Why do relic equipment pieces only get shards when you sell them? Are Shards, or will Shards be used for anything else besides relic gem removal?

The Relic system as a whole will likely be expanded in the future and there will be new purposes for Shards.