I have this fully built MRobin that I love. He was one of my very first 5* units. He is +HP, -RES. I just got two more 4* MRobins, one being +SPD, -RES, the other +ATK, -RES.
When I promote one of the new ones with better IVs and merge my old built one to it, will my new MRobin inherit all the skills that my old one has learned, or just the ones equipped?
example: will my new MRobin know TA 1, 2, and 3, or just 3?
Yes, the new 1+1 level MRobin will have all the skills that the other one has. In fact that is how most people do it, if they have many of the same units merge the ones you don't want to keep together while learing their skills and the last one will get a total SP bonus x the number of units you merge into it + 2 stat point for every +1 and they will start out at level 1+? so you can go through and gain all the SP back on yr way to level 40.
Excuse me, but I think the OP asked if the new Robin(s) will receive the old Robin's inherited skills when the Old Robin is merged in to the new one. In that being no.
Heroes only learn skills through Skill inheritance and increase stat value in merging.
Edit: In merging: up to a max merge limit of 10 where all stats are boosted by 4.
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