Oof. I don't have Hector, but I've been trying something similar with Nowi. She was able to bring everyone low but didn't quite kill people, so the first turn with her there leaves her with like 4-5 super low health units to deal with, and very low health herself. I don't think that's something that a 3* level 29ish FRobin can deal with.
Maybe I can try to heal Nowi at least once with Physick from behind the wall. It's the cramped conditions that are screwing me over right now.
I've done it with a Nino and a Julia so far but I nuked the top green Infantry (who survives) and then Dance + Drag Back to clear the choke point. Follow up turn was nuking the two Infantry: green over the wall from outside, this person will tank a blue caster afterwards so keep that in mind, and using my Julia to nuke the blue Infantry. I also moved my dancer into a safe spot because she was like level 20 and not fit to survive being in range. The rest of the map basically suicides into my two casters but F. Robin survives. Move F. Robin in for the kill, do be careful of Defiant Res throwing off your game plan.
My plan does basically involve tanking a WTA disadvantage caster with Julia so you can opt for a better unit here I guess? I just figured a green tome gave me the greatest chance to tank two casters and ideally not kill F. Robin (and, well, my Linde is built more to outright kill things vs Julia still rather vanilla +RES built).
Also, my F. Robin was like level 38 (albeit 4*) for this but she only needed the one shot and had access to two with dance so it wasn't a huge deal at the time.
Everyone should develop a physical tank and a magic tank, and it will make nearly every one of these challenges a lot easier. I don't mean you need hector, but anything that can tank some hits and help separate the enemies makes things sooooo much easier.
Pretty much. I'm more or less satisfied with my arena teams, at least without pulling Ike or SI fodder or Ike, so basically all my stamina spent is future proofing GHB things.