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Stats: IVs + EVs + Natures + Abilities

Gen 3 is the generation where competitive Pokémon's math was finalised. Every individual Pokémon now has a permanent stat profile assembled from four orthogonal layers:

LayerWhat it doesWhen setVisibility
Base statsThe species' baseline in each of 6 stats (HP, Atk, Def, SpA, SpD, Spe)Fixed at species design time — Charizard is CharizardPokédex entry
IVs (Individual Values)Hidden 0–31 per stat — genetic variation within a speciesAt capture / hatch — randomHidden until much later in the series
EVs (Effort Values)0–252 per stat, max 510 total — earned by defeating opponentsAccumulates through play, cappedHidden — visible only via in-game judges
NatureOne of 25; gives +10% to one stat / −10% to another (or neutral)At capture / hatch — randomVisible on Trainer Memo
AbilityPassive effect (Blaze, Levitate, Drought, etc.)Random between species' 1–2 options at captureVisible on Pokémon Info screen

The combination produces a profile that is fixed for that individual Pokémon and very rarely manipulable after the fact. The Pokémon you have is the Pokémon you have.

POKéMON SKILLS panel — Torchic Lv 10. ITEM: NONE / RIBBON: NONE. Stats: HP 29/29, ATTACK 18, DEFENSE 13, SP. ATK 20, SP. DEF 17, SPEED 12. EXP. POINTS 733, NEXT LV. 9The visible stat panel — six stats, integer values, current/max HP. Behind these numbers, four hidden layers (Base + IV + EV + Nature) determined the result. The player sees the final number; only competitive players go looking for the layers underneath. Source: Game UI Database.

The stat formula

Each stat is computed:

Stat = floor((2 × Base + IV + EV/4) × Level / 100) + Level + 10   (HP)
Stat = floor((2 × Base + IV + EV/4) × Level / 100 + 5) × Nature   (others)

So at Lv 100:

  • A 31-IV vs 0-IV difference: up to 31 stat points.
  • A maxed 252-EV stat vs 0-EV: up to 63 stat points.
  • A +10% Nature: up to ~30 stat points depending on base.

Total: a "perfect IV / max EV / +Nature" Pokémon can have ~125 more in one stat than a "trash IV / 0 EV / −Nature" one. This is the gap that motivates competitive breeding.

Abilities — the species-defining layer

POKéMON INFO panel — Torchic. PROFILE: OT/Edd, IDNo.27459. TYPE: FIRE. ABILITY: BLAZE — "Ups FIRE moves in a pinch." TRAINER MEMO: "SASSY nature, met at Lv 5, ROUTE 101."The Gen 3 signature shot. Type, Ability, and Nature are all introduced here on one screen. Each one is set at capture and effectively unchangeable. Source: Game UI Database.

Abilities are passive effects that fire automatically. Most species have two possible Abilities, and the one a specific Pokémon has is rolled when it's caught. Three categories:

  • Stat-modifiers: Huge Power (doubles Attack), Pure Power, Marvel Scale (1.5× Defense when statused), Guts (1.5× Attack when statused).
  • Status-immunities: Levitate (Ground immunity), Water Absorb, Volt Absorb, Flash Fire, Lightning Rod.
  • Effect-on-event: Intimidate (drops opponent's Attack on switch-in), Sturdy (survives KO from full HP), Rough Skin (returns damage on contact).

The most important Gen 3 abilities are the weather summoners:

  • Drought (Groudon): summons permanent sun → Fire moves 1.5×, Water moves 0.5×.
  • Drizzle (Kyogre): summons permanent rain → Water 1.5×, Fire 0.5%.
  • Sand Stream (Tyranitar): summons permanent sand → Rock SpD +50%, all non-Rock/Ground/Steel take chip damage.

These changed competitive Pokémon overnight. Weather Wars — the multi-year competitive era of teams built around one of these abilities — started in Gen 3 and dominated through Gen 6. See weather-and-battle-modifiers.

Natures — the cute drawback

There are 25 natures in a 5×5 grid:

Nature+10%−10%
AdamantAttackSp.Atk
ModestSp.AtkAttack
JollySpeedSp.Atk
TimidSpeedAttack
BoldDefenseAttack
CalmSp.DefAttack
ImpishDefenseSp.Atk
CarefulSp.DefSp.Atk
Hardy / Docile / Bashful / Quirky / Serious(neutral)(neutral)

Five natures are neutral; the other twenty trade. The trade is small — ~10% in one stat for −10% in another — but on a stat that's already been maximised by IVs and EVs, it's the difference between out-speeding an opponent or being outsped.

Functionally, each Pokémon's nature is bonus-with-drawback baked in at the individual level. A Modest Charizard is a special attacker; an Adamant Charizard is a physical attacker; the same species plays differently depending on which one you caught. And you can only catch one nature at a time.

The player-facing UI shows the nature explicitly ("SASSY nature") on the Trainer Memo. The +/- mapping is not shown in-game. The competitive community had to reverse-engineer the nature chart from leaks and testing — a formative moment in the still-young competitive scene.

EVs — the only accumulated layer

EVs are the only piece of this profile that's not random at capture. They accumulate through play:

  • Defeat a Zubat → +1 Speed EV.
  • Defeat a Tentacruel → +2 Sp.Def EV.
  • Defeat a Geodude → +1 Defense EV.
  • (Each species awards specific EVs to specific stats, on a fixed table.)

So where you grind matters. A casual player who levels their Charizard against random encounters ends up with a Charizard with chaotic EVs (some Atk from Mankeys, some HP from Wooper, some Speed from Zubat). A competitive player goes to Route 113 to fight Slugmas (+1 Sp.Atk per kill) for ~250 kills to max out one stat.

The cap is 252 per stat / 510 total, so the optimal allocation is 252 + 252 + 6 across two priority stats. The 6-EV "leftover" is a famous edge case that competitive players spend on a third stat for tiny benchmarks.

This is loadout-as-budget operating on the individual level: 510 EVs is the budget, six stats are the slots, the player decides where to spend.

The 4-move slot — the visible loadout

At any time, a Pokémon knows at most 4 moves. Pokémon have a learnset (~30+ moves over their lifetime), but only 4 are equipped. Adding a 5th means forgetting an existing move, permanently.

BATTLE MOVES — Torchic Lv 10's full moveset visible: Scratch, Growl, Focus Energy, Ember. Three are Normal-type, one is Fire (Ember). PP gauges show usage budget per battle: 35/35, 40/40, 30/30, 25/25The 4-slot moveset is the most visible loadout-as-budget in the franchise. PP (Power Points) is a per-move use limit — strong moves have low PP. Source: Game UI Database.

The 4-slot constraint is the most-felt ongoing decision. Every level-up that offers a new move forces a real trade: drop coverage, drop status, drop a finisher, or skip the new move. This is why moveset advice is a core competitive activity — every Pokémon's "set" is a 4-move recipe.

It is also one of the cleanest examples of loadout-as-budget at the smallest possible grain: 4 slots, hundreds of moves, type-tagged. The constraint is the design.

What this teaches

  • A permanent profile per individual is a 25-year-old design that still works. Every modern monster-collector copies this template. The trick is the unalterability: re-rolling means starting over with that creature, which is a cost players will absorb when the upside is a build that beats theirs.
  • Hidden layers reward the curious without punishing the casual. A child can finish Emerald with no awareness of IVs or EVs. A competitive player obsesses. The game scales smoothly between modes because the depth is invisible unless sought.
  • A 4-slot loadout is enough. Pokémon's 4-move limit has not been raised in 27 years. The constraint is what makes coverage interesting.
  • Natures are a clean version of bonus-with-drawback. +10% / −10% is small enough to feel like personality and big enough to matter at the top end. The bilingual phrasing as a personality trait ("Sassy nature") softens what is, mechanically, a stat tradeoff.

Patterns this exemplifies

  • permanent-stat-profile — the four immutable layers per individual. Uncurated; canonical case in this knowledge base.
  • bonus-with-drawback — Natures (+10%/−10%) and Choice items (boost one stat, lock to one move) are explicit. Most Abilities are pure upside; some are tradeoffs (Slow Start, Truant).
  • loadout-as-budget — at two grains: the 4-move moveset (per Pokémon) and the 510 EVs across 6 stats (per Pokémon). Both produce real opportunity cost.

Released under the MIT License.