For the Attack Ride, it would probably depend on the situation, like you said.
For the Keyblade from Decade, it'd be thematically similar to one of Decade's weapons, or Decade himself; for instance, the Metal Chocobo, which he receives from Cloud Strife, looks like the Buster Sword. It'd also give Sora a little boost reminiscent of Decade's powers.
For the Keyblade from Decade, it'd be thematically similar to one of Decade's weapons, or Decade himself; for instance, the Metal Chocobo, which he receives from Cloud Strife, looks like the Buster Sword. It'd also give Sora a little boost reminiscent of Decade's powers.