— Fiel to Chlammy, reassuring her that they're friends.
Fiel Nirvalen (フィール・ニルヴァレン, Fīru Niruvaren), who usually has her name shortened to Fii, is an Elf girl who is Chlammy Zell's game partner, as well as the one who helps her cheat using her elven magic. Despite her young physical appearance, she is actually around 52 years old.
It is subsequently revealed that Chlammy is actually her family's slave. Despite this, they hold a close relationship between each other. She even begs Sora to restore Chlammy's memories after the latter won them in a game. Believing that Sora's going to fulfill his words to unite all races, she now works with Chlammy to claim the leadership of Elves as she cares more about Chlammy than her own race.
She is part of the Nirvalen family which may be a factor of her strong magic as a result of being a descendant of Think Nirvalen.
Fiel has long golden hair with a pink ribbon that keeps a portion of her hair in a plait and eyes with dark blue irises and pink clover-like pupils. She has a rather large bust. Her outfit has an olive green and pale yellow creme color scheme.
Despite looking like a stereotypical brainless chick, she's actually very cunning and intelligent. While usually smiling and speaking with a soft voice, she can get serious when the situation calls for it. She also harbors a slight hatred for Flügels, particularly Jibril, as they killed a great number of Elves in the past. However, this is nothing compared to her disgust towards Dwarves, so much that she claimed she will die if she were to stay in the Subterrane together with Nýi Tilvilg for 6 hours.
She greatly cares for Chlammy, even risking her life for her during the Existence Othello game. Despite having pride as an elf, she is willing to swallow it for the sake of Chlammy. It's also implied that her affection towards Chlammy is more than simple friendship, as she would purposely lose a chess match with Sora for the sake of a Yuri play with Chlammy.
She is shown to have a sadistic side in her personality, especially towards those that she harbor hatred against. She would ask Jibril to lick her boots and apologize, cheerfully encourage Nyi to blow herself up, and force a Dwarf to be her chair using the Covenants (he secretly enjoyed it).
Finally, she seems to be somewhat sensitive about her age, as shown in the anime.
She is a hexa-caster (able to cast and maintain up to six spells at once), a very rare capability that only an extraordinary few possess. However, to protect and aid Chlammy, she hid her magical prowess from the rest of the Elves, resulting in them believing Fiel to be a poor magician and a disgrace to the Nirvalen name. In Volume 8, she even broke the limit and managed to cast the 7th spell.
She is also very intelligent. As stated by Sora, Fiel was able to grasp Sora's true intentions without the use of magic.
She is very protective of Chlammy and would go to great lengths to keep her safe. This could prove to be a possible extortion factor if Chlammy was ever to be threatened or taken hostage.
As Elves don't use tools, she is horrible in using them. She crushed her arm when attempting to use a dwarven hammer, and caused the Spirit Arms robot to fall over head first the moment it started, even when Sora described that operating the machine is like "moving their own body at will".
- Her name alludes to "Feel", in contrast with her ancestor's, which is literally "Think".
- She is almost a carbon copy of her ancestor, Think Nirvalen. They are not only very similar in appearance, but also in personality and capabilities - both of them are cunning, sadistic prodigious mages having yuri tendencies.
- According to BD Special #5, her chest measurement is 98I. However, as most Elves are slender in figure, busty individuals like Fiel are subjects of mockery. This is the reason Fiel magically suppressed the growth of Chlammy's busts, resulting in her being flat-chested.