Can I save my Inigo?

if you do build him for damage at all, -3 atk wont matter much with a blade tome and increasing his base speed helps with doubles a lot.

If you dont care about his def or res life and death might help him out. Thats how I saved my summer corrin.

Hey there F2P! Here's some advice from someone that has admittedly spent a little on this game but is F2P a vast majority of the time!

I have a +Spd - Def Inigo myself. My personal play style gives stat boosting C skills to any offensive unit that doesn't really need a threaten skill. The most obvious instance of this with my units is keeping the Hone Spd and Hone Atk Laslow and Nino come with respectively. The Hone/Fortify skills are fairly easy to come by so they're always solid choices for units that don't have a set C skill they'd benefit a lot from. Because of this, I suggest running him on a team with someone that has Hone Atk. All of the calculations I did to see what the raven build Inigo could do offensively were done with a neutral stat with no bonuses and he was able to take out the main things he's meant to be a counter against

He's still one of the best dancers for his potential if you're willing/able to invest (and thankfully only one skill is actually high investment if you get as many Roys as I do). Thanks to the double SP weekend, mine's already fully built because I decided to just spend the feathers I was going to use to promote Cordelia on Cecilia instead. His IVs could be worse if you ask me, and it's not too difficult to work around considering how common Corrin and sword Olivia are. Even if you can't run the raven set, I recommend at least leveling him up to have around as a option for a dancer. Speaking as someone that didn't get a single bride nor summer unit (let alone any 5* aside from Camilla, Jakob, Lucius x2, and Mist for 4 months), it's still really nice to have a high tier unit, even if their ivs aren't optimal.

Pic added to show off what he's like fully built. Yours would have a 37/36/36/22/20 spread. Also ignore the Drive Atk, I just happened to have a second Delthea that was +def -atk. Running Hone Atk from his base kit is prefectly good (although it won't boost his own atk unfortunately), I just had luck dumb enough to be a little extra with my favorite character in all of FE.