Lightning offer page wording

Unknown

I would suggest that the copy under the single Diabolical token button on the Lightning Offer page read:

"Guarantees a featured villain!" (emphasis added)

rather than

"Featured villain guaranteed!"

The latter suggests that I am guaranteed to get the featured villain of the current round, not just a featured villain from the tournament in general.

Unknown

It doesn't really suggest what you're suggesting. Grammatically and technically "featured villain guaranteed" is correct. You're assuming the article the goes in front but there's nothing to suggest that.