Quoted from RtL Rulebook Web Version from FFG:

"In a Copper campaign, a hero can upgrade a

maximum of three of his black dice to silver dice, and may not

upgrade silver dice at all. In a Silver campaign, a hero can

upgrade as many of his black dice to silver dice as he wants,

but only a maximum of three of his silver dice to gold dice. In

a Gold campaign, a hero can upgrade as many of his black and

silver dice as he wants, but only a maximum of one silver die

to a gold die." (pg 23)

How and why does this make sense? So in Copper, you can upgrade 3 black to Silver. Fine. In Silver Campaign you can upgrade all black to Silver and three Silver to Gold. Great. Just Dandy. But in Gold Campaign you can upgrade all black to silver, but only one silver to gold? In the interest of clarity, transferring to Gold campaign is actually a negative thing if a hero is trying to get a bunch of gold dice. Why did they even include five gold dice? It seems to me that a hero would only be able to have four dice at any time: three they upgraded during silver campaign level, and the one they are allowed to upgrade during gold. The wording: "a hero can upgrade as many of his black and silver dice as he wants" makes sense, but the way they threw the ending on throws me the curve. Any rule-gurus out there catch this snafu and want to clear it up?

I believe this is a typo.

You can upgrade three dice to thelevel above the one you're on. There are of course no such thing as (gulp) diamond dice.

I'm aware of no official ruling, but I've always interpreted it as if the last phrase was a typo. That is, as if the last sentence was:

• "In a Gold campaign, a hero can upgrade as many of his black and silver dice as he wants."

I suspect they were thinking of the Overlord's monster upgrade options, which adds the 'Diamond' level. But again, it's not in the FAQs, and I can think of a (rather contrived) reason why the designers would write it that way: they wanted to encourage Heroes to explore more dungeons and acquire more treasure items, rather than make a beeline for trainers.

Another interpretation is that they got the last two levels mixed up. Maybe it should be:

• "In a Copper campaign, a hero can upgrade a maximum of three of his black dice to silver dice, and may not upgrade silver dice at all. In a Silver campaign, a hero can upgrade as many of his black dice to silver dice as he wants, but only a maximum of one silver die to a gold die. In a Gold campaign, a hero can upgrade as many of his black dice to [not and] silver dice as he wants, but only a maximum of three of his silver dice to gold dice. "

...which feels a tad more balanced.

Here is a recent thread on this topic: http://new.fantasyflightgames.com/edge_foros_discusion.asp?efid=4&efcid=1&efidt=7235&efpag=0#8498. I'm too tired to make heads or tails of it, but I thought it might be of interest.