Wanted to add some details in case you're wondering why AutoCrimson's suggestions are solid.

Quote Originally Posted by Unregistered View Post
SMy secondary is Light( with Michael(Aw), Sol(Aw), Light Nike, Diana/Demeter. Like I said earlier, I want to grab SSR Artemis to speed up my Shadow Gem farming. Is she my best option or should I go with someone else? - No Managarmr either
SSR Arty is valued for her A frame def down and nuke. Lugh has the even rarer C frame def down, nukes harder and bursts faster. Tish has B frame atk/def/rst down, has a skill that significantly increases TA, which helps speed up the slowest member of the team so you can burst faster, which can mean that adding Tish actually adds more dps than adding SSR Arty despite Tish not nuking as hard. Tish also has a single target full heal that is just an awesome emergency button for when consecutive DATA procs on the same character.

Also, if you find that battles often end before turn 11 such that Light Nike isn't really adding much value to the team, consider switching her for Diana, who has A frame def down and will stack with Tish and Lugh but not with SSR Arty.

Quote Originally Posted by Unregistered View Post
The only 100% eido I have is Hraesvelg but I'm not sure what kind of team I can build with Titania, El, and Aether.
El sucks on her own, but can make a decent berserk build if you have Morgan. There are two routes you can go with this:

A. mtix Gaia as suggested by AutoCrimson and awaken her. Ex Morgan's guard skill and cast it on Gaia after her own guard expires but when her invulnerability is still up. Titania, Aether and El will all speed up the team so you should be bursting often to reset El's 2nd ability CD for HP and fortitude. Morgan can heal El as a last resort. Your goal is to keep El alive for Morgan's second rampage.

B. go full glass cannon and go with AutoCrimson's Azazel suggestion. After the first rampage and FB, you can just let El die - teamwide guaranteed DATA with rampage is a ton of damage, even if it's just 1T and is particularly good for debuff resistant stuff. Also, against thunder, this is teamwide DATA rampage with critical chance from Aether, do not underestimate that.