ESW stands for Event Storage Warp. Is a glitch that involves the usage of a second file. What it does is store a location in the main file and quitting, loading the second file, void out without previously storing a location, and you'll respawn in the location you stored in the main file. Upon saving + quitting, the second file will be overwritten with the main file's data, and the location will be the same as the main file's, so for example, you could get the gold fang in Walled 1 and go back to Thorntail Hollow with the fang still in your inventory. Death warping can also be used. This works different for Walled City tho, as you remain in Walled City 1, but with Walled City 2 elements active. This allows for a sequence break, useful for speedruns.

RESW stands for Reverse Event Storage Warp. This glitch is done in the same way ESW is, except instead of storing the location in the main file, it is stored in the setup file. When you void out in the main file, it will be overwritten with the setup file's data instead, and all the progress will be transfered. So if your setup file was at the end of Walled city 2, you stored the location and quit, and you void out in a starting file in Krysta'ls segment, it will take you straight to Walled City 2 but with all the data and progress from the setup file, so the main data ceases to exist.