Nordic Ashes

You cant unlock the Catrina achievement by following the normal description, it's been changed. To find what you really have to do you need to look at the description for the Catrina skin for Amaranth. When in the character selection screen before chosing a run, go to the Amaranth character. Below the character you'll see and interaction to swap between the skins. Swap between them until you see the Catrina skin. Currently it tells you to complete a run on 5 of the 7 realms (maps). Shouldn't matter which ones and I don't think the difficulty matters either. It's been changed once so it might change again in the future. You should unlock the achievement at the stats screen at the end of your 5th run.