MegaMan.EXE performs Double Soul with SearchMan.EXE. In MegaMan Battle Network 4, an invisibility-elemental Battle Chip is required to be sacrificed, while in MegaMan Battle Network 5, a cursor chip (such as CircleGun) is required.
- Lock-on: In both games, the moment MegaMan unites with this Double Soul, it immediately locks onto the nearest enemy or boss if they've just taken a hit and flinched, leaving them open to damage again.
- Search Shuffle: The Search Soul can allow the player to shuffle his current unselected Battle Chips (not including Regular chip) up to 3 times, which can be useful to use a Program Advance.
- Removes Invis and underground enemies.
- Charge Shot: Scope Gun (a 5-shot gun that locks on to the nearest panel the enemy is on. Enemies underground and invisible enemies are affected by the gun. In MMBN4, it hits for 10 damage per hit, and in MMBN5, it starts at 12 damage per hit and gains a 2 damage power boost for any additional levels to the Buster Power)
- Weakness: The Scope Gun can miss if the enemy is very fast, and MegaMan is immobile while the Scope Gun is in effect, allowing the enemy to counterattack.
- Bosses to use against:
- Any boss - Performing the Unison while they are still invulnerable after being hit from a flinching attack leaves them open to your next attack, allowing for faster deletions. The Search Shuffle ability is also good for trying to piece Program Advances together. Search Chaos' Dark Circle also has great coverage, and with a few Area Grabs, cannot miss while also standing a chance to hit many times.
- Search Soul's Search Shuffle ability is practically vital for any folder, be it for sifting through unneeded chips or forming Program Advances.
By sacrificing the Darkchip DarkCircle, MegaMan performs a Chaos Unison with Search Soul. His Charge Shot becomes a DarkCircle attack, which stops time, locks on to 7 panels, and deals 300 damage to each it hits. However, it cannot strike the middle panel, and misses one panel each time it circles around (although this keeps it from destroying Mystery Data) To eliminate this problem, a useful combo is to use Area Steal or MetaGel chips to grab more panels. This works best by stealing panels until there is 1 column left and then use DarkCircle. The cursors will overlap, resulting in multiple shots to a panel as many as three times. DarkCircle can pulverize even the strongest viruses (aside from the guard-protected ones) in no more than two hits, and when used with perfect skill, waste a boss in seconds flat while stopping time.
While investigating stolen data, SearchMan and MegaMan confront DesertMan.EXE who is using invisible Mettaurs to steal them. In the ensuing battle, SearchMan refuses to sacrifice MegaMan and they are nearly defeated. But SearchMan gives MegaMan Search Soul and DesertMan is defeated.