Inti Creates has recently announced during last weekend during Anime Expo 2017 that they will be adding new characters to Blaster Master Zero.
Shantae and Shovel Knight will soon be joining the game as extra alternate characters to the game. Similar to Azure Striker Gunvolt, both characters will feature unique move-sets.
The pricing details are:
EX Character: Shantae – 7/6/2017~7/19/2017
EX Character: Shovel Knight – 8/3/2017~8/16/2017
*After their free download period has ended, characters will become paid DLC.
Source: Inti Creates