BPoHC full version upgrade list

Main: First character selected. Determines the player speed, hitbox and regular shot.
Sub: Second character selected. Determines your bomb and flash bomb.
Support: Third character selected. No effect besides applicable skills.

---Yabusame Houren---
Upgrade: Increases the barrier gauge.

Skill 0: Higgs Juice (unlocks at upgrade level 5)
 -HP slowly regenerates.
 -Usable as: Main

Skill 1: Thin Dimensional Fault (unlocks at upgrade level 10)
 -You get two additional barrier gauges.
 -Usable as: Main, Sub or Support

Skill 2: Warp Kingdom (unlocks at upgrade level 20)
 -You can warp from one side of the screen to the other while invincible (bomb, flashbomb, getting hit, etc).
 -Usable as: Main or Sub

---Tsubakura Enraku---
Upgrade: Increases the speed at which the destination gauge moves.

Skill 0: Monochrome Ray -Flash- (unlocks at upgrade level 5)
 -Flash bomb becomes a wide, vertical rectangle that deals damage to enemies.
 -Usable as: Sub

Skill 1: Bird's Eye "Deep Crimson Eyes" (unlocks at upgrade level 10)
 -Automatically dodge out of the way if you hit a bullet. (You might end up dodging into another bullet, though.)
 -Usable as: Main

Skill 2: Black Wings (unlocks at upgrade level 20)
 -Bomb now covers the whole screen, *and* ignores Stage 6 and EX bosses' bomb barriers. Exquisite.
 -Usable as: Sub

---Shion---
Upgrade: Increases the HP gauge.

Skill 0: Id-kun (unlocks at upgrade level 5)
 -Summons a familiar to home in on and attack enemies automatically.
 -Usable as: Main or Sub

Skill 1: Es-chan (unlocks at upgrade level 10)
 -Summons a familiar that drifts around and attacks any enemies in range.
 -Usable as: Main, Sub or Support

Skill 2: Superego-san (unlocks at upgrade level 20)
 -Summons a familiar surrounding the player that drains enemy HP to restore yours.
 -Usable as: Main

---Taira no Fumikado---
Upgrade: Increases deathbomb time. *Note: You can only deathbomb at the moment an HP gauge runs out; doing so refills the gauge.

Skill 0: Inherited Iron-Body Legend (unlocks at upgrade level 5)
 -Bullets touched during Armor Mode are reflected back at the enemy.
 -Usable as: Sub

Skill 1: Seven Shadows (unlocks at upgrade level 10)
 -Adds three Spare Barriers. They regenerate over time like regular barriers, but unlike regular barriers, a gauge that has been outright lost cannot be regained (except by using a Barrier Bomb). Also, the "Dimensional Destruction" sub-event only drains a single barrier gauge, and the "Barrier Interference" sub-event is completely nullified.
 -Usable as: Main, Sub or Support

Skill 2: Flask's Guardianship (unlocks at upgrade level 20)
 -Armor Mode's invincibility period lasts for a short time after Armor Mode itself wears off.
 -Usable as: Sub

---Fujiwara no Iyozane---
Upgrade: Shrinks hitbox (and graze-box).

Skill 0: Spirit Cannon "Promotion Bazooka" (unlocks at upgrade level 5)
 -Flash Bomb gets larger and deals damage to enemies.
 -Usable as: Sub

Skill 1: Spirit Fire "Blaze Returning" (unlocks at upgrade level 10)
 -Summons a bullet-erasing ghost that orbits the player.
 -Usable as: Main

Skill 2: Spirit Body (unlocks at upgrade level 20)
 -Briefly become invincible when the Flash Bomb gauge is completely filled.
 -Usable as: Main, Sub or Support

---Tsugumi Umatachi---
Upgrade: Decreases the speed at which the destination gauge moves.

Skill 0: Pumpkin Rocket (unlocks at upgrade level 5)
 -Doubles movement speed while you're not shooting.
 -Usable as: Main, Sub or Support

Skill 1: One Yellow Eye (unlocks at upgrade level 10)
 -Auto-bomb upon getting hit (negates the hit). Auto-bombing uses up two bombs.
 -Usable as: Main

Skill 2: Low-Quality Genes (unlocks at upgrade level 20)
 -Restores HP when a barrier gauge completely fills up.
 -Usable as: Main or Sub

---Tenkai Zuifeng---
Upgrade: Increases flash bomb invincibility period.

Skill 0: Four Gods' Interstice (unlocks at upgrade level 5)
 -Start with four additional barriers.
 -Usable as: Main

Skill 1: Desperate Strength Barrier (unlocks at upgrade level 10)
 -Bombs received upon losing a life may become special bombs (Power, Barrier, etc).
 -Usable as: Main or Sub

Skill 2: Nemuri-Neko (unlocks at upgrade level 20)
 -Once a barrier gauge starts to regenerate, it immediately fills all the way up.
 -Usable as: Main, Sub or Support

---Sukune Katano---
Upgrade: Reduces power loss upon losing a life.

Skill 0: Haniwa Cage (unlocks at upgrade level 5)
 -You can hold 2 additional bombs.
 -Usable as: Main or Sub

Skill 1: Haniwa Hand (unlocks at upgrade level 10)
 -Items on screen are slightly drawn towards the player.
 -Usable as: Main, Sub or Support

Skill 2: Haniwa Knuckle (unlocks at upgrade level 20)
 -Flash bomb now fires a big, damaging fist!
 -Usable as: Sub

---Sese Kitsugai---
Upgrade: Lowers the autocollect line.

Skill 0: Absooooooooorb!! (unlocks at upgrade level 5)
 -Upon defeating an enemy, the time until the barrier gauge refills is slightly reduced.
 -Usable as: Main, Sub or Support

Skill 1: Bone Skewers (unlocks at upgrade level 10)
 -Flash bomb now deals damage and clears more bullets.
 -Usable as: Sub

Skill 2: Necropotence (unlocks at upgrade level 20)
 -Triggers a free flash bomb upon getting hit. (You still take damage, though.)
 -Usable as: Main or Sub

---Kuroji Shitodo---
Upgrade: Reduces money (booze) lost upon using a continue.

Skill 0: Reverse Linking (unlocks at upgrade level 5)
 -Small chance of replacing one sub-event with "Sake Mongerer" (automatic money event).
 -Usable as: Main or Sub

Skill 1: Sumptuary Edict (unlocks at upgrade level 10)
 -Sometimes bombing won't use up a bomb.
 -Usable as: Main, Sub or Support

Skill 2: Black Wings [Shitodo] (unlocks at upgrade level 20)
 -Large increase to attack power when you have no barriers or lives left.
 -Usable as: Main

---Hooaka Shitodo---
Upgrade: Increases power you get from power items.

Skill 0: Double Meaning (unlocks at upgrade level 5)
 -Sometimes collecting a bomb item will give you two bombs.
 -Usable as: Main, Sub or Support

Skill 1: White Out (unlocks at upgrade level 10)
 -Instead of the default flash bomb, Hooaka's flash bomb now temporarily freezes all bullets on screen. Bullets can still be grazed, but don't hurt to touch. *During boss fights, the bullets are not erased upon unfreezing. Watch out!
 -Usable as: Sub

Skill 2: Aura Wind (unlocks at upgrade level 20)
 -Creates a small field around the player that does huge damage to enemies and occasionally erases bullets.
 -Usable as: Main

---Aoji Shitodo---
Upgrade: Decreases damage taken.

Skill 0: Finest Soul (unlocks at upgrade level 5)
 -You get one additional HP gauge.
 -Usable as: Main or Sub

Skill 1: Insurance Bomb (unlocks at upgrade level 10)
 -Increases default bomb stock by 1.
 -Usable as: Main, Sub or Support

Skill 2: Life Kept in Reserve (unlocks at upgrade level 20)
 -Halves damage taken upon getting hit.
 -Usable as: Main

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*Skills from bosses apply to any character in any role.

---Souko Shirami---
Upgrade: Increases the HP gauge (less than Shion, but cheaper).

Skill 0: Stone's Lifespan (unlocks at upgrade level 10)
 -Reduces damage to HP by 25%.

---Mitsumo---
Upgrade: Increases the barrier gauge (less than Yabusame, but cheaper).

Skill 0: Monster-Revealing Mirror (unlocks at upgrade level 10)
 -You get an additional barrier.

---Kurohebi---
Upgrade: Increases the barrier gauge regeneration speed.

Skill 0: Afterimage Brought to Mind (unlocks at upgrade level 10)
 -Creates a stationary clone of the player upon Flash Bombing. Enemies may aim at the clone for a while instead.

---Jun Amanomiya---
Upgrade: Increases attack power (by a small amount, but cheap).

Skill 0: Satellite Parasol (unlocks at upgrade level 10)
 -Intermittently fires bullet-erasing parasols in an upwards arc while shooting.

---Medias Moritake---
Upgrade: Increases graze-box size.

Skill 0: Re-Thrill (unlocks at upgrade level 10)
 -You can graze a given bullet more than once.

---Kujiru Kesa---
Upgrade: Increases item collection radius.

Skill 0: Sticky Slug Trap (unlocks at upgrade level 10)
 -Falling items will rest at the bottom of the screen for a while.

---Shou Amamori---
Upgrade: Decreases speed at which items fall.

Skill 0: Slug Scramble (unlocks at upgrade level 10)
 -Items below you on the screen fall slower.

---Kunimitsu Ooya---
Upgrade: Increases attack power (by a lot).

Skill 0: Great Upset (unlocks at upgrade level 10)
 -Damage dealt to bosses increases, but damage dealt to enemies slightly decreases.

---Kaisen Azuma---
Upgrade: Decreases the time until the barrier gauge starts to refill.

Skill 0: Tsukuba Toad Oil (unlocks at upgrade level 10)
 -Upon taking damage to the HP gauge, the time until the barrier gauge starts to refill is cut in half.

---Lumen Celeritas---
Upgrade: Increases invincibility time after getting hit.

Skill 0: Cross Feuer (unlocks at upgrade level 10)
 -Upon taking damage to the HP gauge, a small cross that erases enemy bullets appears on the player's position.

---Kaoru Kashiwagi---
Upgrade: Increases the player's defense.

Skill 0: Miasma Shot (unlocks at upgrade level 10)
 -Enemies will become poisoned upon being shot, gradually losing HP. The poison stacks, which is particularly useful for boss fights.

---Garaiya Ogata---
Upgrade: Increases the size of the bullet-cancelling wave emitted upon losing a life or barrier.

Skill 0: Shadow Shiki (unlocks at upgrade level 10)
 -Sometimes clears the screen of bullets upon getting hit.

---Hibaru Kokutenshi---
Upgrade: Increases the amount of money (booze) you obtain.

Skill 0: Money Bill (unlocks at upgrade level 10)
 -Quintuples the amount of money (booze) you get from capturing a Spell Card. Exquisite!!

---Adagumo no Saragimaru---
Upgrade: Makes the flash bomb gauge fill up more easily.

Skill 0: Self-Sacrifice (unlocks at upgrade level 10)
 -Flash bomb gauge gradually fills automatically.

---Fujiwara no Shirogane no Sanra---
Upgrade: Increases the chance that the player's shot will get critical hits (indicated by a small red explosion), which do more damage.

Skill 0: One Trigger Kill (unlocks at upgrade level 10)
 -Randomly deals huge damage to all enemies on screen.

---Para---
Upgrade: Slightly increases the chance that, instead of getting a Game Over upon losing your last life, you'll come back to life with restored barriers.

Skill 0: Clone Revival (unlocks at upgrade level 10)
 -As long as you have more than a certain amount of HP, damage that would be fatal will instead leave you with 1 HP in the gauge. (Some characters' default HP is below the amount needed for the skill to take effect, so they'd need HP upgrades first.)

---Ooama no Ake no Mitori---
Upgrade: Restore a slight amount of HP upon defeating enemies.

Skill 0: Cancel Arrow (unlocks at upgrade level 10)
 -High chance of erasing one sub-event. (Might erase a beneficial one, though.)

---Taira no Chouki---
Upgrade: Increases the chance that any given enemy appearing on screen will be cursed (indicated by turning purple), rendering it unable to shoot any bullets.

Skill 0: Chain-Link Vengeance (unlocks at upgrade level 10)
 -Enemies may explode upon being defeated. Explosions clear bullets and deal heavy damage to other enemies.

---Clause---
Upgrade: Gradually damages all enemies on-screen. Damage depends on the player's power level.

Skill 0: Profundity of Darkness ~ Wormhole (unlocks at upgrade level 10)
 -Attempting to flash bomb without a full gauge will place a warp point on your position. Upon successfully flash bombing, you will warp to the warp point.

---Adagumo no Yaorochi---
Upgrade: Increases the hitbox of the player's bullets.

Skill 0: Cloud-Mowing Sword (unlocks at upgrade level 10)
 -Clears the screen upon filling the flash bomb gauge. The gauge becomes slightly harder to fill, though.

---Suzumi Kuzu---
Upgrade: Decreases the chance of sub-events occurring.

Skill 0: Replay & Experience "REPLAY" (unlocks at upgrade level 10)
 -The mini-map will display colored squares to indicate certain events.

---Xeno a---
Upgrade: Decreases the chance of enemy waves leveling up.

Skill 0: Inevitable Miracle (unlocks at upgrade level 10)
 -25% chance of negating any hit taken. (The hit counter still goes up, though.)

---Yago Ametsukana---
Upgrade: Increases the radius in which enemies can get hit by your bullets.

Skill 0: Blood-Lacquered Sheath (unlocks at upgrade level 10)
 -Temporarily increases attack power upon defeating a boss character. Increases by a larger amount as you defeat more bosses.

---Haiji Seniri---
Upgrade: Reduces boss HP.

Skill 0: Spell Collector (unlocks at upgrade level 10)
 -Obtain another barrier each time you capture a Spell Card.

---Tsurubami Senri---
Upgrade: Increases the amount of damage you can do to enemies during the "Immortal" sub-event.

Skill 0: Crane's Voice (unlocks at upgrade level 10)
 -Reduces the amount of midbosses present in a given stage.

---Suzumi Kuzu (EX)---
Upgrade: ???? (Not yet implemented)

Skill 0: ???? (Not yet implemented)

Skill 1: ???? (Not yet implemented)