Out of the three available areas to explore in Tears of the Kingdom (sky, land, and underground) the Depths presents the toughest challenge to players. The dark realm underneath Hyrule offers strong enemies and navigation puzzles that test even the best players. Among the most fearsome dangers in the Depths are Frox, giant one-eyed monsters with big gaping gobs.
There are 40 Frox in total, and if you plan on upgrading the Depths Armor set, you will need to take out several of them. Here is a rundown of how to track down all three different types of Frox in Tears of the Kingdom.
For a comprehensive guide that pinpoints the exact location of each enemy, check out this map from Progameguides.com.
The first type of Frox you will find in Tears of the Kingdom is just a regular Frox, no descriptors needed. There are twelve of them in total and defeating them will give you Frox Fangs, Guts, and Fingernails.
The majority of standard Frox in Tears of the Kingdom can all be found in the lower center of the map. They are spread out from the Giants Grove towards the Abandoned Gerudo Mine in a diagonal line. The biggest outlier is the final Frox, which hangs out in the top right corner of the map near the Abandoned Eldin Mine.
The next tier of Frox is the Obsidian Frox, of which there are 15 in Tears of the Kingdom. Defeating an Obsidian Frox will get you Frox Guts, Fingernails, and Obsidian Frox Fangs.
The Obsidian Frox can be found in four clusters spread out across the map. The first three all live in the area of the Abandoned Gerurdo mine. There is also a lone Obsidian Frox south of the Floria Canyon Mine. Another cluster of four surrounds the general area of the Abandoned Lanayru Mine. The final grouping of Obsidian Frox covers a wider area running from the Abandoned Hebra Mine up towards the Gleeok Den.
The final — and toughest — tier of Frox in Tears of the Kingdom are the Blue-White Frox. There are 13 in the game, and defeating them nets you Frox Guts and Fingernails (like the other types of Frox) as well as Blue-White Frox Fangs.
Blue-White Frox is the most spread out Frox in Tears of the Kingdom, with no central location. There are four loose areas they reside in, however. A lone Blue-White Frox can be found near the Ancient Observation Deck. Another two are directly north of the Abandoned Kara Kara Mine. The next three are in the surrounding area of Hyrule Castle. Finally, the remaining Blue-White Frox can all be found in the top left of the map, surrounding the Abandoned Hebra Mine and towards the Ploymus Canyon Mine.
After finding and defeating all of the Frox in Tears of the Kingdom you should have explored the majority of the Depths as well as collected all the materials you need to fully upgrade the Depths Armor set — and then some.