I've returned to the game recently and the only new mechanic I'm not quite sure how to optimally use is the ally support. If anyone could suggest me the best supports, I've got: A completely built Brave Lyn, Nowi, Lucina, Hector, Effie and Sharena. A halfway built Alm and Julia. And an untouched Marth, Legendary Ike, Ryoma, Lilina, Fjorm, 2 SP!Xander, 2 Cordelia, Ursula, Soren, 2 SP!Camilla, 2 Takumi and Kagero. (All lv40 5*)
Ally support gives, if I recall, +2 to str/spd/def/res if the unit is right next to the ally that's supported to it (with S rank) and +1 to those stats if 2 spaces away.
It's best to use it on units that are normally near each other, like a melee tank and a ranged glass cannon, for example.
I would use it on allies that are of the same movement type and/or are frequently paired together. Pairs that jump out are Hector and Effie as well as Lyn and Xander. I often pair the legendary heroes with someone with the blessing conferred, for example, I have Arvis paired with Gunnthra, so Consider synergies that Fjorm and Ike might have with other heroes in your roster and let them use ally support.
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