Bossender is a mythical sword wielded by Ione which she received from Entity just before the Crash. It's use is still unknown today and Ione remains mysteriously vague in the series, with not even Kolb knowing of her whereabout. It is one of the 12 weapons forged by Entity
Bossender resembles a longsword, with a thin blade constructed of orical. In the brief shot seen of it in Quest Mode, the blade looks almost complete, implying Ione has had more luck finding the shards of her blade then Kolb with Critbringer.