The literal meaning is "corpse" or "body". On Gaea, they’re necromancers who reanimate corpses (animate forms, or colloquially “skins”) and occupy them with magic while keeping their souls hidden in a remote location. They tend to be hard to kill, even if their bodies are easy to destroy. There are weaker variations called demilīc and much more powerful versions called archlīc. The term has two common, alternate pronunciations: /lɪtʃ/ (litch) and /laɪk/ (like).