Stellaris Build - Best Defense Empire

Key ethics: Fanatic Militarist
Key civics: Reanimators, Warrior Culture
Key traits: Resilient, Very Strong
Key origin: Subterranean
Key traditions: Adaptability, Supremacy, Unyielding
Key perks: Eternal Vigilance
Key edicts: Desperate Measures, Fortify the Border, Fortress Proclamation
Key policies: No Retreat War Doctrine
Key agendas: Impenetrable Border
Key buildings: Planetary Shield Generator, Dread Encampment

Optional civics: Fanatic Purifiers
Optional traits: Lithoid, Noxious, Strong,
Optional perks: Grasp the Void
Optional planet decisions: Martial Law

Defense platform: Whirlwind Missiles
Starbase: Communications Jammer, Target Uplink Computer

Defense Platform Fire Rate:
Desperate Measures edict +40%
Fanatic Militarist +20%
No Retreat War Doctrine +33%
Supremacy: Overwhelming Force tradition +10%
Unyielding: Bulwark of Harmony tradition +15%
Sum: +118%

Defense Army Damage:
Adaptability Survival of the Fittest tradition +25%
Resilient +50%
Supremacy adoption +20%
Very Strong +40%
Warrior Culture +20%
Sum: +135%

Orbital Bombardment Damage Reduction:
Adaptability Survival of the Fittest tradition 25%
Subterranean 75%
Unyielding: Never Surrender tradition 25%
Sum: -125%