Act as a seasoned fantasy illustrator with 10+ years of experience in game design. Create a striking, high-detail logo for a [MEDIEVAL-FANTASY] card game called [LEGEND OF THE ETERNAL REALMS]. The logo should feature a [MYTHICAL CREATURE] (e.g., dragon, phoenix, or griffin) intertwined with arcane runes or glowing magical symbols. Use a bold, gothic-inspired font with metallic or enchanted textures. The color palette should evoke [MYSTICAL ENERGY]—deep purples, shimmering golds, and eerie blues. Ensure the design is scalable for card backs, packaging, and digital branding. Include subtle elements like floating crystals or ancient tomes to reinforce the game's lore-rich theme.