I don't have any units with those skills. Well, i lied. My 5-Star Fir and Klein have Glacies, while my 5-Star Reinhardt has Luna but no way am i sacrificing them. I only come across 5-Stars once in a blue moon.
But eh, Night Sky, Glimmer, and Astra have proved useful to me. Likely because i'm a F2P-player, meaning i have to work with what i get.
I completely understand not always having the best SI fodder, since I'm f2p too, but all of the skills I listed come off of 3* units. Sometimes I don't have 1 of these skills, but tbh it's rare to not have *any* of these skills lol.
Bonfire - Adult Tiki and Male Robin
Ignis - Henry and Female Robin
Iceberg - Shanna and Niles
Glacies - Felicia and Fir (I commend your 5* Fir, but Fir is also in the 3-4* pool, so wait until you get a second Fir for this)
Moonbow - Odin and Palla
Luna - Frederick and Catria
All of the units listed above except Female Robin are available in the 3-4* summon pool.
Night sky, glimmer, and astra can work in many situations decently well, but to give you an idea of why the way their damage scales differently struggles, I'll mention what happened not that long ago in Tempest Trials for me. I was using my bonus unit, Lyn vs a Tempest Trials Beruka. Beruka had glimmer, my Lyn had galeforce, and she had it charged so she could attack that Beruka twice in one turn. Beruka, despite being at weapon disadvantage, tanked my Lyn really well, and was able to take both rounds of her attacking, and Lyn was attacking twice each round lol. My Lyn ended up having to attack 3 whole rounds, 2 attacks per round, for a total of 6 hits, before being able to take down that Beruka (Beruka is very tanky defensively lol).
Glimmer, when charged, did 0 damage to my Lyn, same as all of Beruka's regular attacks (yay weapon triangle advantage). Lyn had no fear of Beruka, despite having to take several hits to KO her. If that Beruka had had ignis instead of glimmer, Beruka would've been able to deal 35 damage from Ignis alone to my Lyn. Beruka had a killer axe, which reduces ignis's charge time to 3 instead of 4, so with Lyn attacking her so often, she could've activated it at least once, maybe even twice, depending on the circumstances of what order the units attacked in. If my Lyn had any chip damage on her at all, she would've lost to Beruka, even though Lyn has weapon triangle advantage over Beruka.
Beruka does 0 damage with Glimmer when she is at weapon triangle disadvantage.
Beruka does 35 damage with Ignis in the same circumstances.
Night sky, glimmer, and astra work when you already have an advantage against your opponent. They don't work very well at all in disadvantageous match-ups. Pretty much all of the other specials will work well in both disadvantageous match-ups as well as advantageous match-ups. That's pretty much the gist of what I meant.
It doesn't matter that much, so I won't mention this again, I just thought an example to help clarify what I meant earlier would help, since having the right special helps some units out soo much.
Damn, with Innes being +atk -hp, he's able to one-shot Lynn&most archers without retaliation. If they are merged or buffed, remember Innes Legendary bow effect + the recent support system are an pretty good method to let him survive anything.
Source: Got +atk Innes too!
I really reccomend letting his cancel affinity stay on him tho, as there are so many cecilia's around lately...
Yeah, I was thinking of experimenting with him with his owl bow and cancel affinity, and using him in arena assault, where I do see raven tome builds decently often. I'm not sure who I'm going to pair him with for supports yet, but I'll definitely enjoy experimenting with who he works out well with to find him the perfect partner in my barracks lol.