FFIV DS Sylph Cave Summon Yang
The Sylph Cave is like the passage to The Feymarch (Land of Summoned Monsters for those of you not playing the DS version), as you will need Float cast upon everyone to avoid damage.
Sylph Cave B1 : Northeast are two treasures, Angel Arrows and a Bestiary. There is another treasure through the wall east but you can't quite reach it. Just take the exit to the southwest.
Sylph Cave B2 - There are two exits here, one northwest of where you start and one from a path directly south of where you start. Take the northwest one to get to B3. Go north here to grab the Hi Potion, Maiden's Kiss and Faerie Rod.
Back to the entrance of B3. Directly east through the wall and head north and then east. You will be by some empty treasures and a path to the north part of B2.
With this northeast B2 path, you can go east and south to see four treasures; 3000 gil, 2000 gil, Remedy, and a Bomb Core. Further south for another chest, and a hole in the ground that lets you fall to the southeast part of B3. Grab the treasures first; Emergency Exit, an Ether, two Maiden's Kisses and complete the B2 map for another Silver Apple. There does not seem to be much here after falling down, but if you travel all the way north and west through the wall you will reach a warp south of those empty chests. You can grab the B3 map's item, a Silver Apple, as well. Take the red teleport. This takes you to the Sylph's Cache.
Sylph's Cache : There are six treasures here. Starting from the southwest treasure going counter-clockwise, you have the Moonring Blade (2 Elder Treants and Malboro), Avenger Sword (two Malboro enemies), Medusa Arrows (two Tunnelers), Blue Fang (4 Evil Dreamers), White Fang (4 Evil Dreamers), and a Red Fang (4 Evil Dreamers). East of here is a set of stairs going down, which leads you out of the Sylph Cave!
Back to the original fork in B2. Take the south exit to go back to B1, this time the south end of it.
B1 : Back to B1, you can go east for a save point in the southeast corner, and then go northeast through the wall to reach the previously inaccessible chest netting you an Elven Bow. In the southwest corner is another path to B2, and you can go further west for two chests, 1000 gil and a Cottage. Might as well take the alternate path to B2.
Southwest B2 path : Start heading north and take the first east passage to go yet another B1 path. A ton of treasures are north of you, starting with an Arctic Wind, Golden Apple, Soma Drop, Ether and Hi Potion. Plus, you get a Silver Apple for completing the B1 map. Back to the southwest B2 path, and go north to find a passage to B3 and an eastern route through the wall that leads you to a Mage Masher sword, but you have a Bog Witch and 5 Bog Toads to deal with. Back west and take that B3 path.
Northwest B3 Path : Head immediately west through the wall for an Elixir. Now go south and east to reach a house. Inside, you can visit with the Sylph's. Grab the Kiku-Ichimonji and Aura Staff in the house. Yang will be sleeping but you can talk to the Sylph's. Taking the upper staircase allows you to leave without trekking all the way back.