diff --git a/src/BattleParamsIndex.cc b/src/BattleParamsIndex.cc
new file mode 100644
index 00000000..05020b5c
--- /dev/null
+++ b/src/BattleParamsIndex.cc
@@ -0,0 +1,115 @@
+#include "BattleParamsIndex.hh"
+
+#include <phosg/Filesystem.hh>
+#include <phosg/Strings.hh>
+
+#include "Loggers.hh"
+#include "PSOEncryption.hh"
+#include "StaticGameData.hh"
+
+using namespace std;
+
+string BattleParamsIndex::Entry::str() const {
+  string a1str = format_data_string(this->unknown_a1.data(), this->unknown_a1.bytes());
+  return string_printf(
+      "BattleParamsEntry[ATP=%hu PSV=%hu EVP=%hu HP=%hu DFP=%hu ATA=%hu LCK=%hu ESP=%hu a1=%s EXP=%" PRIu32 " diff=%" PRIu32 "]",
+      this->atp.load(),
+      this->psv.load(),
+      this->evp.load(),
+      this->hp.load(),
+      this->dfp.load(),
+      this->ata.load(),
+      this->lck.load(),
+      this->esp.load(),
+      a1str.c_str(),
+      this->experience.load(),
+      this->difficulty.load());
+}
+
+void BattleParamsIndex::Table::print(FILE* stream) const {
+  auto print_entry = +[](FILE* stream, const Entry& e) {
+    string a1str = format_data_string(e.unknown_a1.data(), e.unknown_a1.bytes());
+    fprintf(stream,
+        "%5hu %5hu %5hu %5hu %5hu %5hu %5hu %5hu %s %5" PRIu32 " %5" PRIu32,
+        e.atp.load(),
+        e.psv.load(),
+        e.evp.load(),
+        e.hp.load(),
+        e.dfp.load(),
+        e.ata.load(),
+        e.lck.load(),
+        e.esp.load(),
+        a1str.c_str(),
+        e.experience.load(),
+        e.difficulty.load());
+  };
+
+  for (size_t diff = 0; diff < 4; diff++) {
+    fprintf(stream, "%c ZZ   ATP   PSV   EVP    HP   DFP   ATA   LCK   ESP                       A1   EXP  DIFF\n",
+        abbreviation_for_difficulty(diff));
+    for (size_t z = 0; z < 0x60; z++) {
+      fprintf(stream, "  %02zX ", z);
+      print_entry(stream, this->difficulty[diff][z]);
+      fputc('\n', stream);
+    }
+  }
+}
+
+BattleParamsIndex::BattleParamsIndex(
+    shared_ptr<const string> data_on_ep1,
+    shared_ptr<const string> data_on_ep2,
+    shared_ptr<const string> data_on_ep4,
+    shared_ptr<const string> data_off_ep1,
+    shared_ptr<const string> data_off_ep2,
+    shared_ptr<const string> data_off_ep4) {
+  this->files[0][0].data = data_on_ep1;
+  this->files[0][1].data = data_on_ep2;
+  this->files[0][2].data = data_on_ep4;
+  this->files[1][0].data = data_off_ep1;
+  this->files[1][1].data = data_off_ep2;
+  this->files[1][2].data = data_off_ep4;
+
+  for (uint8_t is_solo = 0; is_solo < 2; is_solo++) {
+    for (uint8_t episode = 0; episode < 3; episode++) {
+      auto& file = this->files[is_solo][episode];
+      if (file.data->size() < sizeof(Table)) {
+        throw runtime_error(string_printf(
+            "battle params table size is incorrect (expected %zX bytes, have %zX bytes; is_solo=%hhu, episode=%hhu)",
+            sizeof(Table), file.data->size(), is_solo, episode));
+      }
+      file.table = reinterpret_cast<const Table*>(file.data->data());
+    }
+  }
+}
+
+const BattleParamsIndex::Entry& BattleParamsIndex::get(
+    bool solo, Episode episode, uint8_t difficulty, EnemyType type) const {
+  return this->get(solo, episode, difficulty, battle_param_index_for_enemy_type(episode, type));
+}
+
+const BattleParamsIndex::Entry& BattleParamsIndex::get(
+    bool solo, Episode episode, uint8_t difficulty, size_t index) const {
+  if (difficulty > 4) {
+    throw invalid_argument("incorrect difficulty");
+  }
+  if (index >= 0x60) {
+    throw invalid_argument("incorrect monster type");
+  }
+
+  uint8_t ep_index;
+  switch (episode) {
+    case Episode::EP1:
+      ep_index = 0;
+      break;
+    case Episode::EP2:
+      ep_index = 1;
+      break;
+    case Episode::EP4:
+      ep_index = 2;
+      break;
+    default:
+      throw invalid_argument("invalid episode");
+  }
+
+  return this->files[!!solo][ep_index].table->difficulty[difficulty][index];
+}
diff --git a/src/BattleParamsIndex.hh b/src/BattleParamsIndex.hh
new file mode 100644
index 00000000..94d25b50
--- /dev/null
+++ b/src/BattleParamsIndex.hh
@@ -0,0 +1,60 @@
+#pragma once
+
+#include <inttypes.h>
+
+#include <memory>
+#include <phosg/Encoding.hh>
+#include <random>
+#include <string>
+#include <vector>
+
+#include "EnemyType.hh"
+#include "StaticGameData.hh"
+#include "Text.hh"
+
+class BattleParamsIndex {
+public:
+  struct Entry {
+    le_uint16_t atp; // attack power
+    le_uint16_t psv; // perseverance (intelligence?)
+    le_uint16_t evp; // evasion
+    le_uint16_t hp; // hit points
+    le_uint16_t dfp; // defense
+    le_uint16_t ata; // accuracy
+    le_uint16_t lck; // luck
+    le_uint16_t esp; // ???
+    parray<uint8_t, 0x0C> unknown_a1;
+    le_uint32_t experience;
+    le_uint32_t difficulty;
+
+    std::string str() const;
+  } __attribute__((packed));
+
+  struct Table {
+    parray<parray<Entry, 0x60>, 4> difficulty;
+
+    void print(FILE* stream) const;
+  } __attribute__((packed));
+
+  BattleParamsIndex(
+      std::shared_ptr<const std::string> data_on_ep1, // BattleParamEntry_on.dat
+      std::shared_ptr<const std::string> data_on_ep2, // BattleParamEntry_lab_on.dat
+      std::shared_ptr<const std::string> data_on_ep4, // BattleParamEntry_ep4_on.dat
+      std::shared_ptr<const std::string> data_off_ep1, // BattleParamEntry.dat
+      std::shared_ptr<const std::string> data_off_ep2, // BattleParamEntry_lab.dat
+      std::shared_ptr<const std::string> data_off_ep4); // BattleParamEntry_ep4.dat
+
+  const Entry& get(
+      bool solo, Episode episode, uint8_t difficulty, EnemyType type) const;
+  const Entry& get(
+      bool solo, Episode episode, uint8_t difficulty, size_t entry_index) const;
+
+private:
+  struct LoadedFile {
+    std::shared_ptr<const std::string> data;
+    const Table* table;
+  };
+
+  // online/offline, episode
+  LoadedFile files[2][3];
+};