So, after finding out fate extella link has scathach in it, I started seriously considering playing it.

However, I know the extella series is a sequel to Fate/Extra so I was wondering how necessary it is to have played Extra before Extella? Like, are there plot or world elements I won't understand at all without starting from the beginning? Or is it some kind of continuity reset where they mostly explain everything so that I'm not missing out? Is the anime a good enough substitute for the game?

any advice would be appreciated.

It's a very vague sequel- like, Nero and Tamamo (2 of the 3 servants you could have in Extra) will talk about "winning the grail war", Gawain will make a few references about his master in Extra, etc. But there's very little that directly spoils it, like the identity of the final boss, or secrets about the MC

Apparently there's a few lines from Gilgamesh and Elizabeth that allude to extra CCC too, but that wasn't even translated and I still know barely anything about that game's plot

You can skip it not problem, just know "There was a holy grail war, and you won" and the game will explain itself. I think it operates on a hypothetical scenario where Nero and Tamamo teamed up rather than just having one of the two, but that's the most jarring difference from the original game plot

Haven't seen the anime, but I'd imagine it should be fine for plot purposes and shorter than a LP

Honestly, I'd recommend playing Fate/Extra, even if it didn't give some context into certain aspects of Extella and Extella Link.

The main thing you'd learn about Extella from Extra is regarding the nature of the Moon Cell, how Nero and Tamamo (and other servants) know of each other, why Tamamo and Nero are so fixated on Hakuno, why Hakuno is in the position they're in, and some other miscellaneous details. The good thing about Extella is that, while playing Extra does give further insight, it isn't necessary to understanding the plot of Extella.

Also, Extra's characterization of Tamamo no Mae is far more fair towards her than Extella (which I swear was written as a Nero-centric scenario, considering all the ass-kissing and focus on her. And I even like Nero, but Tamamo is nowhere near as much of a bitch in Extra as the translation made her in Extella).

In other words: play both regardless. They've got entirely different mechanics in game play, and in my opinion, Extra does a better job characterizing Nero, Tamamo, and Emiya.

Also, only watch the anime after playing the PSP game. The anime has some pretty cool fights, and does some interesting things later in, but otherwise it doesn't live up to the game.

I was probably gonna play extra anyway, but i wanted to know how critical it was to extella as far as plot. Maybe I can play both concurrently like I'be been doing with xenoblade 1&2. I'm a little scared though as, between nero and tamamo, I think Tamamo is way more to my tastes but everyone says playing as tamamo makes the game way harder. Nothing against Nero, but none of the saberfaces really do it for me after arturia. I may have to just bite the bullet on that one though.

Picking Tamamo does make the game harder.

.....at first.

Early game with Tamamo is tough, due to her low ranked strength and having the least HP of the three characters. But after you get her three spells that beat Attack, Break, and Shield (respectively), as well as a mystic code that restores SP, the game becomes a lot easier. Pump up her magic and endurance stats and by late game, you're wrecking enemies left and right.

My recommendation? Play through the game with Nero or Emiya first (Nero if you want to not be punished too hard while getting a feel for the Rock-Paper-Scissors battle mechanics) to completion, then play New Game+ with Tamamo to make things a lot easier for when you're using her. New Game+ has some incentives to play it, such as being able to pick the other between Rani and Rin to be a partner depending on which of them you picked in your first playthrough, some new dialogue between servants during battles, and a secret boss. Plus, New Game+ lets you keep all the mystic codes and items you obtained in your first playthrough, and the data you got on enemies carries over and can be increased further.

bit of a cheaty life-hack, but if you wanted to properly play a tamamo game with less stress, consider downloading a completed save file where you can start with a new game plus- most/all common ememies should have their rock/paper/scissors patterns revealed so it'll be easier to coast and level grind while still keeping some challenge for the bosses