Grisaia no Kajitsu has two sequel VNs ("Grisaia no Meikyuu" and "Grisaia no Rakuen") which might be presently in the whole process of staying translated. Moreover, There may be an anime that addresses some information in the VN however it is normally advisable to read the Grisaia visual novel over http://reiduivgr.suomiblog.com/novelwell-an-overview-16617121