Nah gains the most, but you are just bringing someone mediocre to above average. Avatar's Lucina has the best support skill pool in the game. Alternatively, 3rd gen Morgan is going to be your best single unit in the game (unless he doesn't have Galeforce). --- This sentence is as meaningless as you.
I believe it's best to have MU be the parent of Noire, Nah, or Kjelle. They inherit Pegasus Knight from him. As for FeMU... Well, there's not many choices. Either Lucina or a 3rd Gen. Morgan. --- If you fully love and believe in Jesus Christ and are 100% proud of it, please put this as your signature. I'm proud to believe in Jesus Christ as my Savior.
I believe it's best to have MU be the parent of Noire, Nah, or Kjelle. They inherit Pegasus Knight from him. As for FeMU... Well, there's not many choices. Either Lucina or a 3rd Gen. Morgan.
Kjelle doesn't need MU all that much because the Vaike aka Teach exists. MU only gives a small bump over Vaike for Kjelle while MU gives a HUGE bump for Nah, Noire, and Owain. --- Master of all things Fire Emblem Canon.
MU is the only way to make him a viable physical unit without wasting a parent that's better left to someone else. --- OP tomes, high Res, and skills be damned; I won't use Sorcs. O furious and insane gods! Send me ten-nay, TWENTY of your finest cakes!
don't waste MU's premium manseed/FeMU's premium eggs on first generation units --- I may not agree with what you have to say, but I will fight to the death for my right to fight you to the death. -Stephen Colbert