The login bonuses being so hidden is pretty shitty. There's also this: http://m-page.onstove.com/epicseven/...ommunityNo=988
I'm finally in front of a computer and not responding from my phone so here's an info dump (I'm not reading everything above thoroughly, maybe repeated information):
3*s that matter:
Kiris: Absolutely fucking broken. Kiris is how you farm levels of Golem hunt that are far above you and this let's you cheese higher-tier craftable HP/DEF/ATK sets than you would otherwise have access to. She works by herself but the best usage is to pair her with any or multiple of: Silk, Ravi, Alexa. Destina can tank golem fine, Silk gives you speed up to keep applying more poison, Ravi S3 can stun the healer/buffer helpers (Kiris can extend the stun), Alexa just offers 2 more stacks of poison. I've gotten 8 stacks a few times, average is 6-7. 3 turns of 6-7 poison ticks will kill a Tier 7 Golem. Build full hit.
Tieria: Great for arena. Party readiness up and defense down. Not awesome for PVE except for bosses for DEF-. Build speed + crit/hp/def depending on what you want in arena.
Elson: Free and broken. ATK+DEF buff. Build speed+hp/def.
Alexa: Free and crit monster. Build full crit.
Carminew/e: Good lifesteal + self buffer. Some love her, I'm meh on her. Build life steal or some offensive kit. Many options.
Kikirat and Bask: Free tanks. Get them. Simple.
Lorina: Free and gets a specialty change. Eventually a DPS monster at 6*.
A few 4*s that matter. A lot are good but many are kinda eh.
Silk: Free. Arguably the best unit in the game right now. Build speed + crit/hp/hit/def/anything just mash her speed up as high as possible.
Lots: Decent healer.
Armin: One of the best tanks available.
There's actually a lot more but I don't use them because I use mostly upgraded 3*s or 5*s.
5*
Destina: Arguably the best tank in the game for quest content. Doubles as tank + healer which saves you a slot. Build 6/6 HP.
Ravi: Also can serve as a tank, otherwise great DPS for early content. I've found she falls off a bit later on but that may just be me. Many options, lifesteal being one of them.
Units like Sez and Haste are great DPS. There's a lot of 5* that I don't have and can't comment on. Tier lists are ok, some are garbage and some are fine. The main thing is learning how to utilize your 3* units as some of them are better than 5* all throughout the existing content.
ML units I use: Axeguy + Challenger Dominiel. Stupidly effective combo.
Edit: Schuri is not good. There are some niche builds for him but don't waste resources. Go get some of the free units listed above. Get Silk ASAP.