I've been playing Xenoblade Chronicles X for about 20 hours and I'm liking it so far, but I'm not super happy about the way leveling your party members works. Specifically, it's the combination of having characters gain no experience when out of the party, and constantly having 3 of your 4 party slots filled with the same few required characters for story missions. This means the only effective way to level most of your playable characters is by grinding general missions.

Normally at this point I would ignore the vast majority of the cast and focus on a small number of characters to level. Affinity missions throw a wrench into this. They often require certain characters to be in your party, and they are the side quest missions that actually contain story content. I want to see these.

In the hope that I wouldn't have to grind every character to end game levels to see all the affinity missions I went about looking up all the prerequisites. My focus was on two things.

1. What is the maximum affinity level I need to get the side characters to in order to see all their related affinity missions?
2. What are the player level requirements for affinity missions that require me to have specific side characters in my party?

I figure most of these missions will probably have combat, and the characters that are required to be in your party should be at least somewhat close to that level.

Unfortunately for me, the answer I got was that I need to grind most of these characters to near end game levels. I decided to post the affinity mission character prerequisites here in case someone else is would find this information useful in some way. It contains the name of every potential party member in the game so I put it in the spoiler block below.

After 94 hours and all of the story missions, among many normal and affinity missions, I'm decidedly finished with the game (at least for now), but this is super rad! I was always hoping someone would put together a list like this for easy access. Definitely bookmarking this for later in case I ever end up going back to finish all of these.

Being level 55 and 100+ hours in (still haven't done chapter 12 as I'm doing normal/affinity missions, because personally I LIKE doing them) I find worrying about the level of your secondary characters not a big deal, because if you let them fall behind, then carry them along and murder crazy high level mobs while in your skell and equipping them with exp boost augments on their gear, they level up CRAZY fast.

Also important to remember, heart to hearts give affinity for the character upon completion, doing the first 4 give something like 3/4ths of the 5th heart (if you wait that long, as I did with Elma). Also depending on the answers you give you can earn affinity with the rest of your party that way. Very useful way to level up affinity.

edit: Also Alexa is wrong in your info. She requires 4 hearts for her second affinity mission.

Fixed. Thank you.

NP. Thanks for compiling all this info, tells me quite a few characters I thought I'd want to work ons affinity that I can hold off on and focus on people who will actually get me missions :).

Actually in the middle of Murderesses, after killing the monster but before finding the Orphe and man this is a long ass mission, but super interesting payoff for the normal missions that came before.