Pokémon Chromatic Yellow · Trainer's Field Guide
Kanto's bosses have been rebuilt from the ground up. If your plan is "bring the one type that beats theirs," you're going to get surprised.
Every Gym Leader now brings six Pokémon, not two or three. The early gyms still sit at low levels — but there are a lot more of them.
Each boss carries a second theme woven through their roster and moves, so a single hard counter no longer sweeps the whole team.
Bosses run four competitive moves — STAB, coverage for your usual answers, and a setup or status move — instead of random level-up filler.
The last Pokémon a boss sends out Terastallizes on entry, changing its type and powering up its attacks. Plan your endgame around it.
The short version: bosses are now designed teams that answer the obvious counter. Coverage moves punish your safe switch-ins, the whole squad shares a defensive theme, and the ace flips the board right at the end. Come with a balanced party and a way to deal chip damage, not a single silver bullet.
Boss trainers make deliberate decisions. Knowing their habits is half the battle.
| Boss | Opens with | What it means for you |
|---|---|---|
| Brock · Bruno | X Defend | They dig in — physical attackers hit a wall. Go special or set up alongside them. |
| Lt. Surge | X Speed | They outrun you fast. Don't rely on winning the speed tie; priority or bulk helps. |
| Koga | X Accuracy | Their status and Sound moves stop missing — expect the Sleep/confusion to land. |
| Giovanni | Guard Spec. | Your status moves bounce early — para/sleep won't stick on the opener. |
| Agatha | Dire Hit | Crit pressure. Any hit can spike; don't rely on a thin HP cushion. |
| Misty · Erika · Blaine · Sabrina · Lorelei · Lance · Champion | X Special | Their special attacks ramp each turn. End the fight or force switches before they snowball. |
Every boss's last Pokémon becomes a pure Tera-Type the moment it's sent out, for the rest of the battle.
Terastallizing does two things at once: it changes the ace's defensive typing (its old weaknesses may disappear) and it supercharges attacks of the Tera-Type — moves matching it hit for 2× STAB when the type was already one of the Pokémon's own. Most aces Tera into a type they already had, turning their signature attack into a wrecking ball. A few use it to shed a crippling weakness — watch those closely.
| Boss | Ace | Tera Type | Why it matters |
|---|---|---|---|
| Brock | Onix | Rock | Doubles down — Rock Slide becomes a 2× freight train. |
| Misty | Starmie | Light | Photon Beam (Light) hits 2×; its Light typing shrugs off your usual Water answers. |
| Lt. Surge | Raichu | Electric | Thunderbolt at 2× — get your Ground-type in before it fires. |
| Erika | Gloom | Grass | Energy Ball spikes; pairs with Swords Dance for a real sweep threat. |
| Koga | Venomoth | Sound | Sound attacks blast through the resistances you'd normally lean on. |
| Sabrina | Alakazam | Psychic | Psychic at 2× off a huge Special stat — bring a Dark or Steel wall. |
| Blaine | Arcanine | Fire | Flamethrower turns nuclear; keep something wet and healthy in reserve. |
| Giovanni | Rhydon | Ground | Earthquake at 2×; Rhydon still fears Water/Grass, so save that answer. |
| Lorelei | Lapras | Ice | Ice Beam 2× — Electric and Grass switch-ins get frozen solid. |
| Bruno | Machamp | Fighting | Hi Jump Kick at 2× and Focus Energy crits — Psychic/Fairy is your out. |
| Agatha | Gengar | Fairy | Flips to Fairy: your Dark and Ghost coverage suddenly stops working on it. |
| Lance | Dragonite | Stellar | Sheds the 4× Ice weakness — your Ice Beam plan just fell apart. Hit it hard other ways. |
| Champion | Eeveelution | Ele/Fir/Wtr | Whichever eeveelution his Eevee became, it Teras into its own type. |
Two aces are traps for the obvious plan. Agatha's Gengar Teras to Fairy, so the Dark/Ghost hits you brought for it whiff — bring Poison or Steel too. And Lance's Dragonite Teras to Stellar, erasing the double Ice weakness the whole team otherwise shares; you'll need Rock, Fairy, or raw power to close instead.
Each card lists the full team in send-out order, the ace that Terastallizes, and what to watch for.
WatchWater and Grass still win the day — but the whole team hits back with Ground, and Onix packs Earthquake + Iron Tail, so a frail lead can get chunked. Bring bulk, not just a type advantage.
WatchThe classic Grass switch-in is risky — nearly everyone carries Ice Beam. The Star line runs Thunderbolt to zap your own Water answers. An Electric-type with bulk, or a Grass-type that can take one Ice Beam, is ideal.
WatchGround still shuts down the pure Electrics — but Magnemite and Magneton are part Steel, resisting a lot of what you'd throw and answering back with Flash Cannon. Voltorb and Electrode will Explode on you. A sturdy Ground-type that isn't weak to Steel is the safest lead.
WatchFire or Psychic beats most of the roster, but nearly everyone has Sleep Powder — lead with something you don't mind losing a turn on, or carry an Awakening. Clefairy is the curveball: a Fairy that fires Thunderbolt and Ice Beam to punish your Poison/Fighting answers.
WatchGround and Psychic carve through the Poisons, but the team is built to disorient: Supersonic, Confuse Ray, and Sleep Powder are everywhere, and his X Accuracy opener means they land. Bring status protection and clean, high-power hits so a confused turn doesn't cost you the match.
WatchDark and Steel are your friends, but the psychics run Shadow Ball to punish Ghost/Dark switch-ins and Dazzle Gleam (Fairy) to hit Dark back. Hypno and Jynx bring sleep. A bulky Steel-type that resists both coverage moves is the dream answer to Alakazam.
WatchWater is the instinct — and it's a trap. Rhydon sits in the lineup specifically to eat your Water lead and answer with Rock/Ground. Have a second win condition (Grass, Fighting, a fast special hitter) so his Rock body doesn't stonewall you, and keep your Water-type healthy for the Tera-Fire Arcanine.
WatchWater and Grass answer the Ground core, but the Nido pair carry Ice Beam and Thunderbolt to blow those exact switch-ins away, and his Guard Spec. opener stops you from paralyzing or sleeping the lead. Earthquake is on almost everything — keep a Flying-type or Levitate answer, and save your best Water/Grass hit for the Tera-Ground Rhydon.
No Pokémon Center between rooms. Every team is six deep, and the difficulty ramps hard — bring a full party and plenty of healing.
WatchElectric and Grass punish the Water bodies — but Starmie and Lapras run Thunderbolt to fry your Electric answer, and everyone has Ice coverage to freeze the Grass one. Sing and Lovely Kiss threaten sleep. A Water-resist that isn't weak to Ice (a bulky Water/Steel or a Water-type of your own) rides out the whole room.
WatchPsychic and Fairy wall Fighting — but the Rock backbone (Onix, Golem) fires Stone Edge to snipe them, Poliwrath adds Water/Ice coverage, and Machamp's X Defend + Focus Energy make it a critting brick. A Flying or Grass answer handles the Rock/Fighting bodies; save a Psychic/Fairy hit that survives Stone Edge for the ace.
WatchHer Dire Hit opener means early crits, and Hypnosis + Dark Pulse pressure your switches. The big trick: Gengar Teras to Fairy, so the Dark and Ghost hits you saved for it stop working — bring a Poison or Steel-type to close, and a Ground-type for the gas-Poisons before it.
WatchThe team is stacked with Flying-types, so Electric and Ice tear through the first five — but they hit back with Air Slash, Crunch, and Thunder Wave. The catch: Dragonite Teras to Stellar and loses its 4× Ice weakness, so the Ice Beam that swept the room does little to the ace. Keep a Rock or Fairy-type — or just a very strong neutral hitter — in reserve to finish it.
The final fight. Three of his six are fixed; the last three — and his ace — depend on what his Eevee became, which was decided by how your earlier battles against him played out. Whichever of the three teams you face, the shared core is the same:
| His branch | Fills out with | Ace (Lv 65) |
|---|---|---|
| Jolteon line | Cloyster 61 · Ninetales 63 | Ele Jolteon · Tera Electric |
| Flareon line | Magneton 61 · Cloyster 63 | Fir Flareon · Tera Fire |
| Vaporeon line | Ninetales 61 · Magneton 63 | Wtr Vaporeon · Tera Water |
WatchNo type theme to exploit — this is a well-rounded team that covers its own weaknesses, opens with X Special, and Teras its Eeveelution ace into its own type for a 2× STAB threat. Alakazam and Exeggutor punish sloppy switches with Psychic; Sandslash sets up with Swords Dance. Bring answers to Psychic and to whichever Eeveelution he's carrying, and enough healing to grind through all six.
A few habits that carry you through every boss on this list.
One hard counter gets switched around or Tera'd out of. Build a party that covers several angles.
Bosses never heal HP. Consistent chip damage always adds up — a stall war is one you can win.
Keep the Pokémon that beats the Tera'd ace in reserve; don't spend it clearing the early team.
Sleep, confusion, and crits show up on nearly every team. Full Heals and a bit of bulk smooth the variance.