The Knights of Fianna (フィオナ騎士団, Fiona Kishidan?) were a group of knights lead by Fionn mac Cumhaill in Celtic mythology. Each of them were said to be great warriors, none inferiors to the others, who all adored and swore unwavering loyalty to their lord. They all entrusted their sword, weapon, and lives, to the one life of the great hero, boasted as being a "knight's honor", the "true worth of warriors which is expressed by bards and handed down." After Fion's engagement to Grainne, Diarmuid Ua Duibhne ran away with her despite being seen as Fionn's most noble subject, causing Fionn to mobilize all his resources to hunt him down. He did not fight any of his friends, and was eventually forgiven for his crimes, although Fionn's jealously later proved to be Diarmuid's undoing.
- Caílte mac Rónáin - Praised as being talented
- Conan of the Gray Lashes
- Diarmuid Ua Duibhne of the Love Spot, the one knight who "surpasses even the strongest honor"
- Druid Diorruing
- Goll mac Morna - The "Horror of the Battlefield"