Flaer is a boss character in Fire Emblem: The Binding Blade. He is first seen commanding Arcard of Etruria to flee in Chapter 12: The True Enemy. Flaer is guarding a castle in Missur where Cecilia and Sophia are imprisoned. Flaer guards the castle under orders from Narcian to protect Narcian's reputation as one of the Wyvern Generals of Bern. He is Narcian's lieutenant.
He is also an ambassador of Bern with power on the Western Isles. Zephiel sent him to corrupt Etruria from within, and so he gained the trust of Lords Roartz and Arcard. When at the Isles, he sent a messenger to ask for assistance, and they sent him a War Dragon, Ain.
Flaer first makes a brief cameo appearance in Chapter 13 of the Fire Emblem: Hasha no Tsurugi manga, alongside Zeed and Narcian. He later makes a full appearance in Chapter 24, battling both Gant and Kilmar at the old castle in Missur where he is defeated.
—Flaer's death quote in The Binding Blade.