Here's a comprehensive guide for defeating the Forgotten Specimen in "Final Fantasy 7 Rebirth," including requirements, a detailed walkthrough, strategies, and additional tips:
Requirements:
Forgotten Specimen Boss Guide in Final Fantasy 7 Rebirth
•Location: Fought at the end of the Mako Research Facility in Shinra Manor.
•Party Composition: Barret, Aerith, and Cait Sith are your party members for this fight in Chapter 11, "The Long Shadow of Shinra."
Materia:
•Lightning Materia: For dealing with the boss's Magic Resistance/Immunity.
•Healing Materia: Ensure Aerith has Cure or Pray for party healing.
•Barrier Materia: Useful for reducing damage from the boss's attacks.
•Assess Materia: To understand the boss's weaknesses and attack patterns.
Gear:
•Equip weapons and armor that boost your magic and physical damage, like the Gatling Gun for Barret and Guard Stick for Aerith.
•Consider gear with resistance to Physical or Magic damage depending on the boss's current form.
•Level: Aim for around level 35-40 for a comfortable fight, but good Materia setup can lower this requirement.
Detailed Walkthrough: 
Phase 1:
Forgotten Specimen Boss Guide in Final Fantasy 7 Rebirth
1.Initial Form: The boss starts with a balanced form before transforming.
2.Attacks: Overhead Smash, Tentacle Lash, Thunder, Bio.
Strategy:
3.Use Barret for physical attacks when the boss has Magic Resistance.
4.Switch to Aerith for Magic when Physical Resistance is up.
5.Pressure the boss by forcing it to change resistances by attacking it with the opposite type of damage.
Phase 2 (Transformation to Single Form):
Forgotten Specimen Boss Guide in Final Fantasy 7 Rebirth
1.Red Form (Magic Resistance):
2.Attacks: Focus on magical abilities like Thunder and Bio.
3.Strategy:
4.Use Barret's physical abilities like Focused Shot. Cait Sith's Moogle Knuckle can also deal physical damage.
5.Blue Form (Physical Resistance):
6.Attacks: Physical like Swinging Uppercut, Barbaric Mangling.
7.Strategy:
8.Aerith should use spells, especially within her Arcane Ward for doubled effectiveness.
Phase 3 (Mixed Phase and Final Push):
Forgotten Specimen Boss Guide in Final Fantasy 7 Rebirth
1.Dual Immunity: The boss can now have both Physical and Magic Immunity at times.
2.Strategy:
3.Check the boss's current immunity status under its HP bar to decide your attack type.
4.Use Barret when there's Magic Immunity, Aerith when there's Physical Immunity.
5.Summon Gilgamesh to dispel Reflect if the boss uses it, and Phoenix for healing and Reraise if your party is struggling.
Strategies: 
Forgotten Specimen Boss Guide in Final Fantasy 7 Rebirth
•Exploiting Weaknesses: When the boss shows resistance, attack with the opposite type to force a change. Also, use Barret's Bonus Round and Maximum Fury for Physical Resistance, and Aerith's doubled spells in Arcane Ward for Physical Resistance.
•Synergy Abilities: Use Barret and Aerith's Synergy Abilities to manage the boss's resistances effectively.
•Stagger and Pressure: Aim to pressure by forcing multiple resistance switches, then use Focused Shot or Cait Sith's abilities to stagger.
•Defensive Measures: Use Barrier or Protect to mitigate incoming damage, especially during mixed phases.
Tips: 
Forgotten Specimen Boss Guide in Final Fantasy 7 Rebirth
•ATB Management: Save ATB for when you need to switch attack types or for healing.
•MP Management: Conserve Aerith's MP for crucial moments, especially on Hard Mode where MP items are limited.
•Positioning: Move around to avoid area attacks like Mako Geyser or Malice of the Lost.
•Limit Breaks: Use them when the boss is staggered for maximum damage output.
•Hard Mode: Focus on mastering weapon skills like Bonus Round and Arcane Ward, and use Cait Sith's support abilities like Lucky Slots for buffs.
•Summoning: Save summons for the second phase where you'll need to counter Reflect and heal.
