Mimikyu functions as a field-based physical ace using Misty Terrain to block status conditions while also boosting its own Fairy STAB, while Umbreon's Yawn/Wish supports the team's recovery in a balance build. Garchomp manages the cycle with Stealth Rock. As long as the terrain holds, Mimikyu's STAB moves land reliably without any status-condition worries.
Mimikyu (Life Orb, Disguise): Shadow Sneak / Play Rough / Misty Terrain / Swords Dance. Uses Misty Terrain to turn the field Fairy-friendly, also boosting Play Rough's power as the team's centerpiece.
Umbreon (Leftovers, Inner Focus): Foul Play / Yawn / Wish / Protect. A support that manages the whole team's health with a Yawn/Wish cycle.
Mega Meganium (Meganiumite, Leaf Guard): Solar Beam / Weather Ball / Dazzling Gleam / Trailblaze. Leaf Guard frees it from status conditions, and Weather Ball allows flexible type coverage depending on the weather.
Garchomp (Focus Sash, Rough Skin): Earthquake / Rock Tomb / Dragon Tail / Stealth Rock. A lead that manages the front with Stealth Rock and forced switches via Dragon Tail.
Mega Delphox (Blaze): Overheat / Psyshock / Dazzling Gleam / Nasty Plot. Boosts Sp. Atk with Nasty Plot before sniping the low-Defense wall with Psyshock.
Glimmora (Sitrus Berry, Corrosion): Toxic / Spiky Shield / Power Gem / Earth Power. Corrosion lets Toxic land even on Steel types, an unconventional matchup breaker.