Board Thread:Questions and Answers/@comment-32975343-20170828171820/@comment-6036561-20170829165111

As far as I know yes, the Greater Grail "only" serves the purpose of storing prana and later aid the Masters in summoning the Servant.

For the first, second and so on magic, those are basically unrelated to the Holy Grail War. In short, there are some people who can access to Akasha's power even whitout the aid of the Grail (i.e. Schweinorg, the teacher of the three who set up the first Holy Grail War ritual). Thanks to that they devised some "greater magic" that uses this power (i.e. time travel). The first, second... fifth magic are just that