I guess I need to clarify that Title as I am not sure what the common name for such series is or how one would describe them. Expanded Universe isn't quite what I am getting at, but is the closest thing to it that I can use as a coined term.

What I am describing in this thread are game series that have games with wildly different game styles in different game genres using the same lore. Usually allowing different perspectives on the way the lore works and the world(s) operate.

Some examples will help clarify further.

1) Never played them much or at all in some cases, but World of Warcraft as an MMORPG and Warcraft 1-3 as Real Time Strategy games are good examples of games that give different perspectives on the same lore.

2) Another great example would be the Might and Magic series. There is an sandbox-esque singleplayer RPG series simply called Might and Magic and a Turn-based Strategy Series called Heroes of Might and Magic.

3) The Elder Scrolls as a more relatable example is another one, but barely, and I wouldn't really count it normally, except it is likely an example most here will be familiar with. There were four separate series within the Elder Scrolls universe, now up to five. The Main Series (Arena-Skyrim). TES Adventures: (Redguard). TES Legends: (Battlespire). TES:Travels (Shadowkey, Stormhold, Dawnstar and Oblivion: Mobile). The Elder Scrolls Online. Now I say this isn't a good example because the perspective and how you interact with the world isn't that different in function. You interact as a single person with the world throughout all of them. Whereas in Warcraft and WoW, or M&M and HOMM for example, you see the strategy game's top down perspective in contrast with the RPG/MMORPG's more personal down to earth perspective as an individual player(s).

I find these types of series, that operate alongside one another but with very different perspectives forced upon the player by gameplay, to be fascinating.

I am curious what other people think of such series and what some other series with them are.

A lot of big Nintendo games do this like Mario and Pokemon.

Fallout is sort of like that because it switched companies. 1 and 2 are quite different compared to 3 and New Vegas, and tactics is its own thing.

Although maybe it falls too much into the 'expanded universe' setting, Star-Wars has games in almost every genre.

From space-combat sims (TIE-Fighter) to MMOs (Galaxies and TOR), multiplayer Battlefront to RPG KoTOR, adventure (Jedi-Knight and Jedi-Academy)...and so on. Many of these are in 'series' of their own, such at KoTOR I, and II; Dark Forces, Jedi-Knight: Dark Forces II, etc; TIE-Fighter, X-Wing, etc; I even remember a few RTS games (which were either pretty bad, or too complicated for me to figure out as a 7 year old).

Might and Magic also has Dark Messiah, a first-person action-RPG set in the Heroes of Might and Magic V continuity. It takes place many years afterward, sharing an incredibly important character from the Tribes of the East expansion pack..

Anyway, another such series would be Shin Megami Tensei. This is a massive franchise of mostly JRPGs that draw heavily from world mythology, and involve themes of order versus chaos (usually represented as God versus Lucifer, neither of whom are represented in a wholly positive light). Continuity is incredibly loose even between games of the same series, though there are implications that they all feed into each other and that there's a multiverse at work. The various series include:

• Digital Devil Story: Megami Tensei (based off of a manga)
• Shin Megami Tensei
• Persona.
• Digital Devil Saga
• Devil Summoner
• Devil Survivor
• Devil Children
• Catherine (though this is a puzzle game with a plot)

Final Fantasy has this with the Tactics series. Another one that comes randomly to mind is X-Com. The Ultima series had Ultima Underworld. Even SimCity had SimCopter... probably there are hundreds of them.

In Japanese you call a spin-off story in the same universe a "gaiden", though curiously Ninja Gaiden is not a gaiden...

Shin Megami Tensei is a series, but it has its spinoff series and some of them are quite different

You mean like the Warcraft series of RTS games and that tiny little spin-off, World of Warcraft?