You needn't look to anything outside of the game to find them . I have played many different seeds and there are always crypts in the black forest. Looks like a door, you load into it. The only other thing in BF that you can load into is a troll cave. You'll know if you load into a troll cave. And you will be able to discern between the two.

also there are literally hundreds of "black forest" in any given seed. Do not think that the on e you looked at is the only one.

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