I'd keep him, but I'm a primarily Horus user. You won't be able to easy mode some descended mythical like you can with SoD Luci, but 16x still does mostly fine. Plus he still pairs well with other #x friends.On something like my 40th reroll I finally got a Horus (Lv. 30 due to the godfest). I assume that's worth keeping? My new phone isn't rooted so I can't backup and keep trying for Lucifer. It's getting rather frustrating at this point too, plus I'm missing out on the free stones.
If I keep Horus, any tips on how best to proceed?
Grab a drop of each color from the first dungeons and start working your way up. And from there following the standard path of getting a Siren and few other drops.