If someone is recruiting (or gains units in some other way), but he has no units available because they're all on the board, is he allowed to use some other marker to signify additional units?

Jenna said:

No, you are limited to the actual units the game comes with. If you recruit, and all your units are on the board, you ARE allowed, however, to remove units from other areas to fulfill the recruit if you want.

(Note that this only applies to recruiting; for instance, if you use the Necromancer ability to being Reanimates into the battle, you CANNOT remove units in the case, as it's not a recruit).

The only things a player has that you can use substitutes for are the Activation tokens.

Okay, thanks. One more follow-up question (sorry, I play with a bunch of nit-picky people):

You said, "If you recruit, and all your units are on the board..."

What if I recruit and not ALL my units are on the board, but all of the TYPE of unit that I want to recruit are on the board... am I allowed to pull that type of unit from other areas of the board, or do I have to recruit the remaining units first?

Jenna said:

Sorry, I should have been more clear. Yes, in your situation, you can pull units of that TYPE off the board.

For example, if you are the Undead, and all your Necromancers are on the board, but you still have Reanimates or Dark Knights or Archers left, you CAN recruit new Necromancers by removing existing ones from the board and placing them in the stronghold(s) you are building at. You can also recruit Dark Knights or Reanimates as normal (or Skeleton Archers).

I hope this helps.

Yes, that helps. Thank you!

The rules are not clear in this one, but can you destroy your own units even if you are not re-recruiting them or even if there are still enough in you supply? Meaning you destroy them before executing recruit order, but not build them again... can you do that ? It can be useful to "clear" a path between two players, but you simply cant build those units again because maybe you dont have enough resources.

I think in Starcraft, you can always destroy your own units even you arent executing build order ... but in RW, i dont know ...

No, the only time in Runewars you can voluntarily destroy your own units is if you are recruiting and need to replace them.

This is from Page 31: "These are the only times a player may voluntarily destroy his own units, strongholds, or developments."

The "these are the only times" referred to are the recruiting of units (for the destroying own units), and building strongholds or developments (for destroying those).