RO is a client-server game. When you press a skill key:
The file ragnarok/data/sprite/¸ó½ºÅÍ/À̹ÌÁö/¸ó½ºÅÍ.act (and similar for characters) controls weapon swing speeds. Some private servers with weak anti-cheat allow a "Lite" 0-delay where you replace the heavy two-handed sword swing sprite with a blank, 1-frame dagger swing. This tricks the client into sending attack packets faster. Result: Auto-attack only. Not skills. Ragnarok 0 Delay Sprite Grf
If you delete the .spr file for Meteor Storm, your client will show nothing (or a red error box), but the server will still force you to wait 3 seconds before casting again. RO is a client-server game