The “EX Treasure: Phantasma’ side quest that The Master Trials DLC adds to Legend of Zelda: Breath of the Wild will let you find the Phantom armor from The Legend of Zelda: Phantom Hourglass and The Legend of Zelda: Spirit Tracks.
The Phantom armor set will boost your attack, but you can’t upgrade it at a Great Fairy fountain or dye it at the Kochi Dye Shop in Hateno Village.
Collecting this set will take a bit of running around Hyrule Field, and will bring you up against some super tough enemies. We’ll help you prepare in the sections below.
Misko’s EX Journal: Outpost Ruins
The “EX Treasure: Twilight Relic” side quest for the helmet appears automatically the first time you start the game with the DLC installed. Its text reads:
The royal family of Hyrule collected historically significant outfits, but they were stolen by a bandit named Misko. Anong the items stolen was some phantasmal armor.
There’s a journal that places the locations of the treasure somewhere in the Outpost Ruins…
Head to Ja Baij shrine on the eastern edge of the Great Plateau. Turn directly northeast and paraglide down off the plateau. Continue northeast until you see the Outpost Ruins. Just on the other side of the first wall you see, you’ll find Misko’s EX Journal.
Reading Misko’s EX Journal will update your adventure log for all eight of the stolen relics — Majora’s Mask, the Tingle armor set, Midna’s Helmet and the Phantom armor set. For the phantasmal armor, Misko wrote:
Armor worn by fierce phantoms, feared even by heroes, is hidden in the ruins of Hyrule Field. Find these pieces at a battleground where brave souls tested their skill… at ceremonial ground where royal guards are honored… and at the ruins where the soldiers of Hyrule gathered.
How to find the Phantom Helmet: Coliseum Ruins
The first location mentioned by Misko, “a battleground where brave souls tested their skill,” is the Coliseum Ruins. If you haven’t been here before, it’s just east of the Outskirt Stable and just north of the Great Plateau.
There’s no quick way to get here — you’ll have to do some walking wherever you start. The most direct path is from Kaam Ya’tak shrine where you can find the road that leads straight into the ruins.
Before you go charging into the coliseum, a warning: There’s a lynel in here. There’s no point in the game where fighting a lynel is easy, so be prepared. If you’re going to take it on, make sure you have plenty of healing meals and elixirs and at least one really good weapon. If you’re going to try to avoid it or run in and out without dying, we wish you luck. Let us know how (or if) that worked out for you.
As reader rooislangwtf points out in the comments, if equip the lynel mask from Kilton’s shop, you you can trick the lynel into not attacking you. If you don’t press your luck for too long, the mask will fool it and it won’t attack.
The treasure chest containing the Phantom helmet is buried in the ground against the wall to the northeast — it’s to the right when you walk in.
How to find the Phantom Greaves: Hyrule Garrison Ruins
For the next piece in the set, head to the Central Tower. Turn to the southeast and paraglide down into the Hyrule Garrison Ruins.
There are a couple guardians here that you’ll have to deal with or avoid. Head to the Akkala Ancient Tech Lab to pick up some ancient arrows before you take them on. An ancient arrow will drop a guardian with a single shot to the eye. If you’re careful (or lucky) you might be able to avoid them altogether.
Your goal is a little further to the southeast of the intersection. Look for a broken-down guardian next to a low wall.
How to find the Phantom Armor: Sacred Ground Ruins
The final piece of the Phantom set is waiting for you at the Sacred Ground Ruins. You may have been here before while collecting Captured Memories. Just like getting to the coliseum, you’re going to have to do a lot of walking to get there.
You can start at Katah Chuki shrine and follow the roads to the east, but it’s going to take you through a bunch more guardians. If you’ve got the ancient arrows or like the challenge, go for it.
If you’d rather sneak in the safer way, start walking north-northeast from where you picked up the Phantom Greaves — directly northeast from the Central Tower. You’ll walk onto the Sacred Ground Ruins from the opposite direction. There won’t be any roads to follow, but you’re not going to run into all those guardians.
In the center of the Sacred Ground Ruins, activate your magnesis and look to the southeast. The EX treasure chest is in the water right in front of you. Get the chest up onto the stone with you and open it for the Phantom Armor.