Скачать или смотреть Bartre & Fir Infernal BHB - F2P Clear [No SI] - Fire Emblem Heroes

This Bound Hero Battle was actually kinda tricky to get right. It was enjoyable to try and get this all to work. That green archer was a particular pain.
Also, sorry about the top bar showing the time I recorded this, battery life, etc. DU recorder has suddenly decided video cropping is a premium-only feature.

The following Sacred Seals are used:
Drive Atk on Halloween Dorcas
Hone Spd on Olivia
Iote's Shield on Eir

Notes:
PLEASE REMEMBER THAT DIFFERENT UNITS MAY RESULT IN DIFFERENT ENEMY MOVEMENT PATTERNS.
Eir and Olivia are free copies obtained from Book 3 Chapter 1 part 5 and her Hero Battle respectively. Halloween Dorcas and Ethlyn can be obtained for free through Tempest Trials, but can also be purchased with Heroic Grails. If you need to purchase them with Heroic Grails, you will then also have to upgrade them to 5 star rarity. It is possible that 4 star Ethlyn could replicate this strategy, but I cannot test this. Given how Halloween Dorcas barely survives the red mage flier, I assume 5 star rarity is required for him. I do not know how different IVs or merges affect this strategy.
The Drive Atk Sacred Seal on Halloween Dorcas and Hone Spd Sacred Seal on Olivia is so Eir can obtain the Attack and Speed necessary to defeat Fir when the team first attacks. While the Sacred Seals are upgraded in the video, both Hone Spd 1 and Drive Atk 1 should provide Eir with just enough Attack and Speed to still KO.
The Iote's Shield Sacred Seal on Eir is so she can KO the green infantry archer after Ethlyn attacks.
It is important that Ethlyn attacks the green infantry archer before Eir so that she can apply Fear which in turn allows Eir to not be KO'd.
Make sure to heal Eir before she attacks the red mage flier so that she can activate the offensive boost from Lyfjaberg.
Once Bartre is defeated, the map is practically won. The lance armour does not have an offensive Special, so you can just plonk Halloween Dorcas in front of them and keep him healed up indefinitely while he chips them down.