|Primary caster||Fate Testarossa|
|Japanese name||アークセイバー |
|First app.||Nanoha (ep.4)|
Arc Saber (アークセイバー Āku Seibā) is an unusual shooting spell of Fate Testarossa which can only be used while Bardiche is in Scythe Form. It consists of throwing Bardiche's compressed mana blade at the target like a boomerang.
Although the range is only middling and the projectile speed is not high, it can "bite" barriers and its varying route is more difficult to defend or dodge. Because of this, Fate can use the spell to trick her opponents. Its power is also fairly powerful, as Fate uses it to great effect during her fights against Nanoha Takamachi.
- Haken Saber (ハーケンセイバー Hāken Seibā) is the spell that replaced Arc Saber after Bardiche is upgraded to Bardiche Assault. It can only be used under the Haken Form.
- Haken Slicer (ハーケンスライサー Hāken Suraisā) is the charged variation of Haken Saber in The Gears of Destiny. Despite its lower casting and projectile speed, a blow-away explosion is further generated by the end of the mana blade's hits.
- Split Haken (スプリットハーケン Supuritto Hāken) is the double-projectile variation in The Gears of Destiny when Fate is in Sonic Form. The normal attack fires two Haken Saber projectiles at the same time, while the charged attack fires one Haken Slicer and one Haken Saber.
- Crescent Saber (クレッセントセイバー Kuressento Seibā) is the equivalent of Haken Saber in the movie continuity, as Bardiche Assault's Haken Form is re-designed as Crescent Form.