Double Soul (MMBN4)

Double Soul (ソウルユニゾン Soul Unison) is the main transformation system of Mega Man Battle Network 4, it can only be used by Good MegaMan.

How to Use

To Double Soul, the player must sacrifice the respective element chip to unite with MegaMan (the chip cannot be a Regular Chip). The transformation will last 3 turns or until it is overwritten by another Soul. MegaMan will lose the form when the Emotion Counter hits 0 and he’s in a position where the player can control him. There also are Patch Cards that will allow MegaMan to remain in a Soul permanently.

Each Soul can only be used once per battle.
Normally Souls cannot access DarkChips, but during ToyRobo's ShadeMan fight, the mandatory DarkSword will show up and can be used. It can also used to Double Soul into Proto Soul and be charged up.

Soul Abilities

Red Sun

Guts Soul
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Sacrifice	Panel Destruction chip
Element	None
B Button PowerAttack	GutPunch (60 ATK) Non-flashing. Knocks back 1 panel.
Abilities	None and Panel Destruction chips gain +30 attack power (dimming and non-dimming). GutsMachineGun: Rapidly pressing B (Press B 6 times within 1/6 of a second between each press) will make MegaMan temporarily invincible and execute a rapid fire attack. (5 ATK, up to 8 times)

Fire Soul
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Sacrifice	Fire chip
Element	Fire: MegaMan can walk on Lava panels and is weak to Aqua attacks.
B Button PowerAttack	Flamethrower (50 ATK) Fire attack.
Abilities	Stepping on Lava Panel will have MegaMan consume it and heal 50 HP. Upon Unison, plus-shape panels on both sides of the field spawn Grass panels. A Button PowerAttack: Fire chip (dimming and non-dimming): The chip becomes a Fire Arm that travels down the whole row. (150 ATK)

Roll Soul
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Sacrifice	Recovery chip
Element	None
B Button PowerAttack	RollArrow (30 ATK) The struck target's BattleChips are destroyed.
Abilities	MegaMan heals 10% of his max HP anytime he uses a BattleChip. Does not heal if the chip is used in a cut in.

Wind Soul
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Sacrifice	Wind chip
Element	None
B Button	MegaMan's B Button becomes AirShot (5 ATK).
B Button PowerAttack	WindRacket (50 ATK) Non-flashing. Those struck on impact is knocked back all the way down the row. Otherwise, blows away all enemies.
Abilities	Air Shoes: MegaMan can walk over hole panels. Float Shoes: MegaMan ignores Cracked, Swamp, Ice, and Pitfall panels. Upon Unison, NorthWind takes effect. The enemy's Barrier or Aura are blown away. For 3 turns, a Fan effect is active on the enemy's field. The Fan effect can be overwritten by a Wind or Fan chip. If that obstacle is destroyed, there will be no Fan effect on the field. Wind chips gain +10 attack power (dimming and non-dimming).

Thunder Soul
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Sacrifice	Elec chip
Element	Elec: MegaMan is weak to Wood attacks.
B Button PowerAttack	ZapRing (20 ATK) Elec attack. Paralyzes.
Abilities	All non-dimming None and Elec chips will paralyze. The paralysis applies to all hits of a multi-hitting chip with the exception of ElemSand. Said chip will cause flashing regardless.

Search Soul
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Sacrifice	Invisible chip
Element	None
B Button PowerAttack	ScopeGun (10 ATK, up to x5) Pierces invisible. First 4 hits non-flashing, 5th hit causes flashing.
Abilities	Upon Unison, all invisible and underground enemies are no longer in that state. A Shuffle button appears on the Custom Screen that can shuffle unselected chips with the Folder. This can be used up to 3 times per turn.

Blue Moon

Aqua Soul
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Sacrifice	Aqua chip
Element	Aqua: MegaMan won't slip on Ice panels and is weak to Elec attacks.
B Button PowerAttack	Bubbler (20 ATK) Aqua attack. Charges very quickly.
Abilities	A Button PowerAttack: Non-dimming Aqua chip: x2 the chip's attack.

Number Soul
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Sacrifice	Bonus Point chip
Element	None
B Button PowerAttack	DieBomb (10 ATK x Die Roll) If the Die hits the enemy directly, it will only have 10 ATK.
Abilities	None chips gain +10 attack power (dimming and non-dimming). The Custom Screen displays 10 chips to select from.

Wood Soul
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Sacrifice	Wood chip
Element	Wood: MegaMan will rapidly heal on Grass panels (1 HP every 2 frames, 30 HP per second) and is weak to Fire attacks.
B Button PowerAttack	Twister (20 ATK, up to x8) Wood attack. Non-flashing.
Abilities	Status Guard: MegaMan can't be paralyzed, blinded, confused, or immobilized. If a selected Wood chip (dimming and non-dimming) is followed by a None Chip, the Wood chip consumes the None Chip and its attack power is added to it. One of strongest None chip target for Wood Soul's ability is BlueMoon. Through the Select Battle feature in Network, its attack power can be raised to 600.

Metal Soul
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Sacrifice	Break chip
Element	None
B Button PowerAttack	MetalFist (150 ATK) Breaking. Knocks back 1 panel.
Abilities	Break Buster: The normal buster will have break property. A Button PowerAttack: Non-dimming None or Break Chip: x2 attack power.

Junk Soul
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Sacrifice	Summon chip
Element	None
B Button PowerAttack	Poltergeist (100 ATK per obstacle) Dimming attack, cannot be cut in. All obstacles thrown will be breaking.
Abilities	Upon Unison, all invisible and underground enemies are no longer in that state and all enemies gain confused status. Two recycled "Junk-Chips" appear in the Custom Screen every turn. These are chips you or your opponent have selected in previous turns (they didn't need to used in battle), these include Dark Chips.

Proto Soul
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Sacrifice	Sword chip
Element	None
B Button PowerAttack	WideSword (80 ATK) Sword property. Non-flashing. Can perform counter hits.
Abilities	All non-dimming Sword attacks will not cause flashing. This includes LifeSword Program Advance and DarkSword. B + Left: Reflect. If an attack is blocked, 50 damage is sent down the row. A Button PowerAttack: Non-dimming Sword Chip: x2 the chip's attack and MegaMan warps 2 steps forward while using it. Z Saver and Slasher BattleChips can be charged for x2 attack power but MegaMan will not step forward. Unconventional Sword Chips will require more work. For VarSword and Z Saver commands, the A Button must be pressed down again after releasing it for the charge. For Slasher, the chip must be used instantly.

Glitches

Notes

The following abilities are not explained in the game’s e-mails:
- Fire Soul healing on Lava panels
- Junk Soul removing flashing status
- Proto Soul removing flashing from Sword attacks
Since MegaMan will only lose Double Soul once he regains control, if MegaMan is continuously paralyzed or stunned the turn he’s supposed to lose the form, he will carry the form to the next turn. All Custom Screen abilities will also remain.
Since the Double Soul Patch Cards do not reset MegaMan’s Karma, he will be able to use Evil Chips in Double Soul forms.
The Rockman EXE 4 TGS 2003 trailer showed some early versions of Double Souls:
- Guts Soul was to crack every battlefield panel upon unison. A remnant remains in the final game with Guts Soul shaking the screen upon unison, usually reserved for Souls that alter the field panels.
- Fire Soul was to make every battlefield panel into Grass panels upon unison. It was also to have FireArm as its B Button PowerAttack, attacking more than 3 panels and uses the Buster weapon visual, which was only used for the normal Buster shot visual in the final game.