Debuffs reduce an enemy's buff by HALF at most (never to 0): -300% vs a 600% buff -> 300%; vs 800% -> 500% (limited by your debuff size). Buff percentages ADD across all sources; final stat = base x (totalBuff% + 100%). Flat (absolute) buffs apply AFTER % and are NOT reduced by debuffs -> flat is better for t1-t11, % better for t12+. Observed maxima: buffs over 2800%, debuffs over -1100%. Six buff types by in-game notation: Basic (always on), Marching/'Attacking', In-City ('Defending City'), Defense ('Defending~', only from Blazon/Military Academy/Castle Decoration), Outcity Defense (only Idunn & Freyja), Reinforcing. Which apply depends on combat role: solo/rally attack & camp-defense = Basic+Marching; own-city defense = Basic+In-City+Defense; building/relic defense or reinforce = Basic+Marching+Defense+Outcity. Stacking: sub-city mayor buffs do NOT reach main-city troops, but same-culture sub-cities' own buffs stack; rally participants' buffs never stack (each applies to its own troops). Debuffs: mayor debuffs DO stack when SOLO (sub-city must be alive/in battle), but in a RALLY only the single strongest debuffer applies (-70% + -140% -> only -140%). Max 9 subordinate cities.
Original research source: Evony Guide Wiki
