Sigrun and Tanith are two characters who both appear in Fire Emblem: Path of Radiance and Fire Emblem: Radiant Dawn. Tanith is a playable character in both games while Sigrun is an NPC in the former and a playable character in the latter. Both serve Empress Sanaki of Begnion and act as her caretaker and guardians. Fans have read the two as queer, but they sadly have no support conversations or paired endings to provide further insight into their relationship outside of their screen-time in-game.
Both also appear in Fire Emblem Heroes (the top two in the picture above), notably with Bridal alternate skins. Fans have read this to be hinting at their relationship, as two other characters included in the banner, Louise and Pent, are a couple. However, they both have no dialogue that references the other explicitly.
Because of this, we have classified them as Queerly Rumored/Read.
LGBTQ references in this game series:
Fire Emblem: Thracia 776 (1999): Marty and Dagdar
Fire Emblem: The Blazing Blade (2003): Bramimond; Florina and Lyndis; Legault; Lucius and Raven
Fire Emblem: Sacred Stones (2004): Ephraim and Lyon; Joshua and Gerik
Fire Emblem: Path of Radiance (2005): Ike and Soren; Jill and Mist; Reyson and Tibarn; Sigrun and Tanith
Fire Emblem: Radiant Dawn (2007): Elincia and Lucia; Heather; Jill and Mist; Joke about Ike and Sothe; Kyza; Ranulf
Fire Emblem Awakening (2012): Gay Jokes and Queerness; Same-Sex Relationship Hack; The Hubba Tester
Fire Emblem Fates (2015): Forrest; Nina; Romance options; Same-Sex Relationship Hack; Skinshipping; Soleil; The Hubba Tester
Fire Emblem Echoes: Shadows of Valentia (2017): Leon; Lukas; Queer Readings
Fire Emblem Heroes (2017): Ally Support; Loki; Sharena
Fire Emblem: Three Houses (2019-2020): Byleth Pairings and Controversy; Non-Byleth Pairings
See also QRM’s entry for this game series