A: Use a virtual machine (Oracle VirtualBox) with no personal data. Run a local RO server (rAthena) on the same PC. If the GRF works there, it's only because your local server has no delays. Do not take it to public online servers.

A "0 Delay Sprite" modification alters the game’s .grf (Graphics Revision File) archives. By replacing standard character sprites with modified versions—often just a single, static frame or a "chopped" animation sequence—players effectively bypass the visual "wind-up" and "cool-down" periods of their character's movements. The Competitive Edge

A is a compressed archive containing Ragnarok Online’s visual and audio assets, such as sprites, maps, and sounds. A "0 Delay" version specifically modifies the .act (action) files associated with character sprites.