Undirect links are links between two or more series that happen outside the series themselves. This either means that they happen in another series or outside any series, just being created by official statements. They happen as often as direct links, if not more often, but most times they're ignored in this wiki.
An example of undirect link is characters from two different series meeting in a third series, for example characters from the Zelda series fighting against Pokémon characters in Super Smash Bros. games. This is an undirect link because no element from the Pokémon series ever appeared within the Zelda series or vice versa, but elements from both series interacting with each other together still creates an in-universe link. These types of link are ignored in this wiki because once we tell in the direct link pages that the third series have taken elements from the other two, and interaction between these is just an interaction between two elements of the series, so it's not notable. Returning to the previous example, we have a page for each direct link that happens between the Zelda and Super Smash Bros. series (Super Smash Bros. X Zelda) and between the Pokémon and Super Smash Bros. series (Pokémon X Super Smash Bros.), so once we indicate that the Super Smash Bros. series has Zelda and Pokémon characters, a fight between Princess Zelda and Pikachu is just a fight between two characters in the game, even if not original, so it shouldn't be noticed.
There are exceptions though, for example the "Star Fox" microgame in the game WarioWare: Smooth Moves that while being based on the game Star Fox, features a giant R.O.B. robot as a boss, thus creating an undirect link between the Star Fox and the Famicom Robot series (see Famicom Robot X Star Fox#WarioWare: Smooth Moves). In this case it's notable because the WarioWare series takes elements from other series to make them microgames, that are games within the game, thus being considered sub-universe links (see Star Fox X Wario and Famicom Robot X Wario for these series cases), but the resulting undirect link is an in-universe link, so it's not implied by the original two links. This defines the general rule for undirect links:
If a link between two series happens in another series, it deserves its own article or section, only if its of stronger type than the direct links between each of the two series and the third series.
Another kind of undirect link is represented by official statements. These cases are usually more notable because there's no "third series" in which the undirect link happens, so there also are no direct links implying an undirect link. Many times, however, the official statements come as a confirmation of a previous supposed link. An example is the official statement from Capcom around the time of the release of Street Fighter Zero that the Final Fight series happens in the same universe as the Street Fighter series, creating an in-universe link between them. This time the link was actually implied by the previous cameo of Chun-Li in Final Fight 2, so it's not notable. On the other hand different series created by the same author or company may be confirmed to take place in the same universe while there originally were no connections between them, for example in the case of Thunder Ceptor, a video game by Namco that had no connection to any other series, but was confirmed to take place in the same universe as the Galaxian, Dig Dug and many other series by the same company, when they released the official UGSF Timeline. Therefore the general rule is:
If a link between two series is revealed outside any series, it's only notable if it's of stronger type than the direct links between them.
Note that everytime an official statement confirms something that was even vaguely implied, we always only consider the direct link implied, rather than the undirect link: for example, if the author of a series declares a character from it to be based on one from a previous existing series, even if nobody had originally guessed it, we consider it a direct link happening in the character's first appearance, because it's considered to take place as soon as the character's likeness are seen.