Quote Originally Posted by Unregistered View Post
Main reason to deliberately work on more *'s for an event eidolon is if you think you'd equip it as a sub on any of your teams, be it for stats, for the summon effect, or *ahem* distant future related reason.
Oh, there's also that whole trading in eidolons for a type of currency thing way off in the future, but that's not limited to SSR's. It just takes like 5 SR's to get the same trade-in value of 1 event SSR eidolon.

For Mastema specifically:
1. Her atk is low, so the main reason for her as a sub right now is if you really want that attempt to inflict dazzle ahead of 5 other summon effects.

2. (hypothetical distant future stuff; feel free to skip reading if you're not curious, as this won't be relevant for quite a while)
They gotta keep coming up with slightly different archetypes of event eidolons, right? We've had +character/+hp, +character/+ability, +character/+burst, the three dual +element, and the first of the Lilim series. Soon we'll see the start of pure single +element. And not too far away we'll see the start of +element/+resist (water is the first of this series). Then much later will be the start of +element/+double (again, water is the first of this series). Then later after that is the start of the series that is pure +element, but how much of a bonus it is varies (aaaand water is the first of this series as well).

So, +element where the magnitude of the bonus varies. It varies depending on how many eidolons of the matching element are equipped as subs, I think. Absolute maximum bonus is +50%, whereas the pure +element with no condition caps at +45%. Right now, there's only water and fire in this series, so thunder is something that's way, waaaaay off in the future.
Anyway, doing a quick count, there are 6 thunder event SSR eidolons listed on the wiki: Sandalphon, Ixion, Yggdrasil, Mastema, Meng Huo, and the respective Lilim. Meng Huo's from a collab event with Koihime Musou; whether we actually get that particular event is unknown. So the number of thunder event eidolons we'd have on our side can be either 5 or 6.

Though, it's not important to think about now. It's so far ahead in the future that you can push off working on Mastema until the reprint if a need arises.
Awesome, thanks for the info.
I think with her low atk power and thunder atk% bonus capping at 30% instead of 40% I'll work other stuff, save overworking half elixirs, and leave possibly MLB'ing her til the reprint (which at the rate they are doing them may not actually be that far away). Need to prioritize getting Shot Laser and Devil Javelin to MLB first as they have higher stats then some of my current gridded.