Near the end of February, Nintendo announced that a new "Inherit Skill" feature will be coming to Fire Emblem Heroes sometime this month (March). On the official Fire Emblem Heroes Japanese twitter account, a couple of new tweets were made announcing that the new feature will arrive on 16th March.
【アップデート予告】
先日お伝えした新機能「スキル継承」の追加が、3月16日 16:00に決定！
本日は、「スキル継承」に関して、詳細をお届けします。 #FEヒーローズ pic.twitter.com/gVOkQtVkju— ファイアーエムブレム ヒーローズ (@FE_Heroes_JP) 2017年3月8日
The tweets also gave details to what the new feature can do and the limitations it has.
First, each hero can inherit up to 3 skills.
Secondly, the inherited skills will start off as Mastered on the new hero (hero who inherits the skill).
Lastly, 1.5 times more SP is needed to learn the inherited skills.
Additionally, a tweet was also made saying that hero exclusive skills like Falchion (ファルシオン) cannot be inherited. Depending on the heroes weapon type and movement type, some skills may not be compatible either.