When Honedge evolves, it divides into two swords, which cooperate via telepathy to coordinate attacks and slash their enemies to ribbons.
– Pokémon X Pokédex
Doublade follows the pattern that many Pokemon have: a Pokemon multiplies when it evolves. Doublade went from 1 sword to 2. However, Doublade does not evolve into Triblade, instead one of the blades becomes a shield.
Its family is currently one with the only Ghost/Steel type. Despite being a ghost sword, it still has a gender.
Stat-wise, it has ridiculously high Atk and Defense, at a cost of low Spd and Sp Def.