[Klashikari]

Fate/Zero and Fate/Stay night are 2 series closely connected together as the former is the prequel of the latter.
As such, many points from a certain series may be answered with the other one.

In order to avoid way too many spoilers and questions in the Fate/Zero thread, this thread shall serve for those who are little to not used to a specific chapter of the franchise or those who require a little memory refresh.
For instance, things like "Why the summoning process are so different in Zero and Stay Night?" or "What is "Heaven's feel" can be answered here without any problem.
In short, the sole purpose of this thread is to explain the many connections between Zero and Stay night which were not really clear for some people. This is of course leading to spoilers and whatnot.
However, this is not supposed to be a wiki/full spoiler thread, where "anything and everything" is explained (that is basically the spoiler game thread).

This is basically a very niche and specific thread. A very quick Q&A for anything bridging both franchise. It is -not- supposed to clarify the whole fateverse/nasuverse at all.

It has to be noted that due to the nature of the topic, this will severely spoil you for either Fate/Zero and/or Fate/Stay Night. So please use your own discretion if you want to learn more about the various connections (recurrent characters, events, details, noble phantasm etc) between the 2 franchise.
Therefore, Spoiler rules are -not- applied here, but please only stay ontopic: answer precisely the inquiry posted and avoid extending the answers with needless details.