Ah.

Aha. You're omitting the optional final argument, which means Excel is opting for "approximate match" instead of exact match. This is fine so long as all entries are in alphabetical / numerical order (as is the case with "Nation 1", "Nation 2" etc), but as soon as you change "Nation 1" to "Orcs" it breaks because:

Range_lookup A logical value that specifies whether you want VLOOKUP to find an exact match or an approximate match:

If TRUE or omitted, an exact or approximate match is returned. If an exact match is not found, the next largest value that is less than lookup_value is returned.

**The values in the first column of table_array must be placed in ascending sort order; otherwise, VLOOKUP may not give the correct value.** You can put the values in ascending order by choosing the Sort command from the Data menu and selecting Ascending. For more information, see Default sort orders.

If FALSE, VLOOKUP will only find an exact match. In this case, the values in the first column of table_array do not need to be sorted. If there are two or more values in the first column of table_array that match the lookup_value, the first value found is used. If an exact match is not found, the error value #N/A is returned.

EDIT: Cite Sources {

Microsoft Excel Help: VLOOKUP}

You can verify this behavior by changing "Nation 1" to "Angels" which is still lexicographically lowest in the set; the functions still work fine!

So, in short, to fix your issue you need to tack a FALSE argument in as the fourth parameter to each of your VLOOKUP calls. EDIT: To be thorough: setting Range_Lookup to TRUE (or leaving it blank) means "Do the best you can and give me the closest match, but assume the list is sorted." So actually that works fine so long as you're willing to commit to having your dataset always sorted.

I've had Excel spreadsheet projects where I went CRAZY looking for the cause of this exact problem. Then I figured out what was going on and swore I'd never be so foolish again. Then it happened again six months later. This way lies wisdom, or perhaps madness.