Use Rau's GuaiZ Custom and Rau Le Creuset at least ten times in versus or mission. To unlock Rau's GuaiZ Custom, first buy the development plan of Guaiz Custom. Equip normal GuaiZ with RESERVE MAGAZINE parts that costs 582.000 (S type) and upgrade the normal guaiz until it reach 4500 TP. After that, go to the shop and GuaiZ custom become available for sale.