I understand your hesitation in not investing in 3*. However, you won’t regret investing on some of them. GP has a list of it, but here’s mine based on my own experience:
#1. Melantha. Sure, Franka is good, but she’s expensive to build and plays a slightly different role despite being on the same archetype as Mel. You see, when it comes to assassination, most targets are casters (who has high RES but low DEF) and slugs (low RES and DEF but self-destructs upon death). Dealing with these targets only require high HP and high DPS, something Mel has in spares and at a very cheap cost. There’s hardly an excuse not to build her.
#2. Kroos. You have Exu and BP. They are your primary snipers, focus on them first . But if you ever encounter a map that requires 3 or more snipers, don’t forget Kroos. She’s so easy to build, and she dishes very high DPS.
#3. Steward. You may not have him now, but he’ll come sooner or later. Treat him as your secondary Amiya but with an specialization. This guy actually prioritizes units with high DEF. This means that if you have a wave of enemies, he will prioritize killing those units with high DEF first (and Arts damage ignores DEF). High DEF enemies are the menace in this game. Of course, there is no absolute need to build him. But if you need a guy to erase high DEF units first, then Steward is your man.
Lastly, regarding your core squad, the rule of a thumb is to build at least one for each role. Here’s my recommendation for your current roster:
- Exu and BP would be enough. No need to invest on other snipers unless the map specifically calls for it (like Aerial Threat Supply Map where you farm for Skill Summaries).
- Meteorite would be enough. There might be a situation where Shirayuki would be better for the job, but from my own experience, investing on Meteorite alone is enough.
Single Target Caster
- Amiya is enough unless you have Coebe or Eyja (I’m actually still using Amiya despite having Eyja because I use the latter as AoE caster)
- Gitano is great even if you get Skyfire(5*) or Mostima(6*). Her S2 deals true AoE damage instead of just splash damage and can be used to clear Annihilation 3 (a high-difficulty map where you farm for Orondum; entry level is usually around E1L50)
- This is the class with the most archetype. Their main purpose is to provide ground DPS.
- Typical units: SilverAsh, Lapland, Blaze, Specter, Chen, Bibeak, Astesia, Mousse, etc.
- You can build Franka to help your team with the DPS. Is she worth investing? I don’t know as I don’t have her. But even if I do, I will not build her because I already have a very good team and has no issues with DPS or taking down high DEF units. At the end of the day, it boils down to what you need and what you like.
- Fang and Plume are mainly there just to fill the role while waiting for better units, so no need to invest on them too much. Just level them up enough for you to pass the stage.
- Courier, who is available in Credit Store, is a direct upgrade for Fang
- Vigna is the direct upgrade of Plume. Vigna also works in tandem with Mel for assassination jobs. You can get her via ★4 Recruitment Exchange Voucher.
- Myrtle, who’s only available through Gatcha, is currently the best DP-generator. You don’t have her right now, but once you do, build her.
- Beagle is a role-filler too. Just invest enough to clear a stage.
- Coura is the role model for this job. You can also get her via ★4 Recruitment Exchange Voucher.
- Matterhorn is a niche defender. No need to invest to him early game.
- You can get Gummy for $0.99.
- They are not as tanky as Coura. Their main job is to just block 3 enemies (not necessarily to tank them) while providing healing support to your team.
- Ansel and Hibiscus are just fillers as well. You can buy Gavial in Credit Store to replace them.
- You will need an AoE Medic too. Perfumer ( ★4 Recruitment Exchange Voucher) will do the job just fine although people would usually say that Ptilosis is the best for this role (due to her extra utility)
- You’ll get Orchid as a Mission Reward. She will suffice until you get Angelina.
- You’ll get Shaw and Cliffheart as rewards as well. These two are key units in certain maps, so you can invest on them. Their skill level matters more than their actual level BTW.
- You can get Gravel either via Gatcha or Recruitment (Specialist or Fast-Redeploy tag). She is a crucial unit to bait or stall some specific enemies.
- ★4 Recruitment Exchange Voucher is rather expensive early in the game. The best source of operators early game would still be the Gatcha banners.
- Building a unit usually means leveling a unit to around E1L50 with their skills at Rank 4 at least.
- Being “effecient” is nice, but don’t stress too much on it. Play the game the way you like it; Level operators you like and you think you need.