Hi-Ether

Hi-Ether (ハイエーテル) is an item panel in Kingdom Hearts 358/2 Days, an Item Command that appears in Kingdom Hearts Re:coded and a recovery item in Kingdom Hearts III. In Kingdom Hearts 358/2 Days, it recovers 2 casts of each of your magic you've installed while in Kingdom Hearts Re:coded, it raises Data-Sora's clock level by 2.

Kingdom Hearts 358/2 Days
The Hi-Ether can be synthesized for 1200 munny once Roxas is promoted to Novice rank.
 * 2 Ether

Kingdom Hearts III
Hi-Ether can be synthesized once 12 different synthesis materials are obtained.
 * 3 Wellspring Stone
 * 3 Lightning Stone
 * 3 Writhing Stone
 * 1 Hungry Shard

Kingdom Hearts 358/2 Days

 * Hi-Ether: A chest in the Lotus Forest during Mission 67; a chest at the Agrabah Gate during Mission 68; a chest in the Bizzare Room during Mission 69; two chests at the Halloween Town Square and Boneyard 2 during Mission 79; a chest in the Sandswept Ruins during Mission 82; a chest on the Bridge during Mission 83; three chests in the Underground Passage, the Side Street, and at Tram Common during Mission 89.

Kingdom Hearts III

 * Hi-Ether: Phantom Ship fleet (100%)

Other Appearances
Hi-Ethers were planned to appear in Kingdom Hearts II, and had a sprite developed, but were ultimately left out of the finished game.