The reward for Nintendo's Fire Emblem Heroes tweet promotion — 10,000 hero feathers — is now live. The game has also added additional quests for arena duels that can earn you a few more feathers.
Two days ago, Nintendo promised 10,000 feathers to all Fire Emblem Heroes players if a tweet of theirs reached 10,000 retweets. That promotion reached its goal almost immediately, and the reward is now live for all players. You can get these by logging into the game, and then accepting the gift by tapping on the owl in your castle.
— Nintendo of America (@NintendoAmerica) February 7, 2017
Earning feathers — the currency players need to upgrade the star ranking of their heroes — is pretty difficult in Fire Emblem Heroes, and this update hasn't necessarily made it much easier. Previously, players could earn feathers from winning Arena Duels based on how many points they earned during the week long duelling period. While you could potentially earn 1600 feathers this way, the payout would take a week, and that isn't even enough feathers to take a three star character to four stars.
Now there are Arena Duel quests, which will give you 1000 feathers each for completing a certain number of duels. It isn't a lot, but it's something.
It's still pretty unlikely that you're going to be able to promote any four star characters to five stars any time soon, as the process costs a whopping 20,000 feathers. Still, this update gets you a smidge closer. Maybe a five star Donnel is still in reach?