Badges are spent at the Battlefield Shop (Historic General = 2,040), to unlock/upgrade the Wonder (Lv1/2/3 = 1,700/2,800/4,800), upgrade Dragon->Ares equipment (800/piece), and raise a dragon (~50/feeding, 5/refine + 50 refining stones). Ares equipment and dragon training need huge quantities, so shop carefully. Acquisition is mainly FREE via Battle of Constantinople (BoC) -- NOT available at Battle of Gaugamela. Participating gives at least 180 badges, scaling with win/loss and personal+alliance score; DOUBLED during special battlefield periods (every few months). Personal-score badges (11/22/2024): 1800+ = 620 (win)/500 (lose); 1200-1799 = 570/450; 800-1199 = 480/370; 500-799 = 400/280; 250-499 = 310/230; <=249 = 250/180. Alliance-score bonus: 100 = 10, 250 = 26, 500 = 50, 1200 = 90, 2500 = 150. Battle of Chalons: at least 200 badges, by team ranking and personal score. Paid: the 25000%-return 5th-level pack ($99.99) includes 100 badges. Royal Chest (all three Royal Thieves) may give 5-10 badges. Comment (unverified): some high-level bosses can drop badges. For a bot, badges are a battlefield-participation currency -- earn them by joining BoC/Chalons, and spend on the Wonder, key generals and Ares/dragon progression.
Original research source: Evony Guide Wiki