|Primary caster||Fate Testarossa|
|Japanese name||ディフェンサー |
|First app.||Nanoha (ep.6)|
Defenser (ディフェンサー Difensā) is a barrier-type defensive spell which has lower mana consumption and faster casting speed than the basic E-ranked Protection barrier. By the time of StrikerS, the Modern Belkan system has also developed its namesake spell.
Defenser is the main defensive spell of Fate Testarossa, as she focuses on speed and standalone action. She has set it as her Auto Guard spell so that Bardiche can auto-cast it. It is also presumed that Presea Testarossa, Rynith and Alph uses Defenser instead of Protection in The Gears of Destiny. On another hand, Ginga Nakajima is a known caster of the Modern Belkan version.
In the primary continuity, Defenser's initial visual design is a still barrier in Nanoha and A's. However, its enhanced spell Defenser Plus (since A's) and Defenser itself (since StrikerS) have shared the same visual effect as Protection. Their visual effects have also been redesigned in the movie continuity following Protection's. The following illustrates the changes in visual effects of Defenser and Defenser Plus (self-defense):
- Defenser is first cast by Fate in Nanoha (ep.6) to defend against Nanoha Takamachi's Divine Shooter.
- In The MOVIE 1st, Fate uses it chronologically earlier to defend against the Jewel Seed cat monster, before she sets up her Barrier Jacket and Bardiche. The barrier is, however, cast in a flat form like Round Shield, just like the high-level arrangement of Protection (e.g. StrikerS epilogue).
- In A's (ep.2), Fate uses it to defend against Signum's attacks.
- Ginga is first seen casting Defenser in StrikerS (ep.15) during her mock battle with Subaru Nakajima.
- In StrikerS (ep.22-23), Ginga (brainwashed as Number XIII) also uses it during her fight against Subaru.
- Defenser Plus (ディフェンサープラス Difensā Purasu) is the enhanced version after Bardiche's upgrade. It is first cast in the fight against Signum in A's (ep.7). In StrikerS (ep.17), Fate also uses it in her fight against Tre and Sette. Besides self-defensing, Defenser Plus is also capable of being cast over a larger area to protect other targets in a hemispheric barrier, blocking out gases and fumes from getting into it. Fate has used it in A's (ep.10) to protect Alisa Bannings and Suzuka Tsukimura, and in StrikerS (ep.2) to protect fire victims.
- X Defender is probably a development of Defenser.