A Fighter (sentouki) is the term given to the person in a Unit who takes on the role of spell-casting in a Spell Battle. Their counterpart is the Sacrifice. Fighters control offence and defense in a Spell Battle with their Spells and are expected to follow the commands of their Sacrifice. Fighters have been seen battling by themselves but this is considered somewhat taboo, shown in how Breathless and the female Zeros react when Soubi fights them on his own. It is also considered taboo for Sacrifices and Fighters sharing different names to battle as a Unit. The roles of Sacrifice and Fighter are immutable and cannot be interchanged, nor can it be chosen who acts as which.
The strength of a Fighter is amplified when their Sacrifice is supporting them: until Nisei Akame, a talented Fighter, meets Seimei Aoyagi, he is unable to manipulate anything heavier than one kilogram. However, later in the series Nisei Akame and Soubi Agatsuma are shown fighting by themselves with considerable power, presumably because they are now sufficiently advanced to be able to do so.
Fighters with a destined name will have that name visible upon their body since birth, shown when Natsuo asks Ritsuka's mother whether Ritsuka had any birthmarks as a child and says it's strange that Ritsuka's destined name has not appeared on his body yet. The artificially created Zero series also possess their destined names upon their bodies, although Yamato's destined name disappeared when her bond with Kouya dissolved. There have been no cases where this has happened with non-artificial Units as of yet.
There also exist blank Fighters, such as Soubi Agatsuma, who do not possess a destined name but can be "given" a name according to Ritsu Minami.
Ai Myoujin says that it is usual for Fighters to come first to Seven Voices Academy where they await their Sacrifices.
See also: Category:Fighter