I've been joking since spring that covid is the new geostigma. Walk over the bridge and you'll get to a new area with 5 pipes which are even numbered. Nibel. He tells you about the reunion at Mt. The chocobo will leave you after you get off of it, so make sure you get across the swamp to the south with it.
Make great use of limit break moves to take big chunks out of this thing's HP, and make sure someone can heal the party when necessary. Move through the caves here until you come across a Rude man (that's his name).
A lured chocobo must also be distracted with some greens to eat while you fight the monsters around it. Mt Nibel Jenova Room Question. Steal 3 of them, for your entire active party. Go outside, and exit to the world map by the upper right. Or click here to search for specific content. Now glide #4 when you're back up, and grab the All Materia from the chest. Before you jump in any, walk and climb down the ladders first, until cloud pushes the second one more down.
Be sure to learn it on both Enemy Skill Materia's at this point before slaughtering the creature.
Grab the Counter Materia it was 'keeping', and exit Mount Nibel. Here you can find the Elemental Materia on the ground. Jump off the ledge, and enter the cave below.