As of March 26th, 2020 you are able to unlock guaranteed characters by collecting and using Character Shards!

When you buy a named bot bundle or receive a duplicate bot you will receive Bot specific Character Shards. You can then exchange those shards for a crystal that guarantees that bot through the MIA section and the new Bot shop in the Build menu.

When you buy a bundle or get a duplicate of any bot or C.O.M.B.A.T. bot, you will be seeing this new currency marked with the prism crystal on top of existing duplicate rewards.

You will get the following amount of shards from duplicates:

4-Star: 500 Character Shards
3-Star: 100 Character Shards
2-Star: 20 Character Shards

Character Shards will remain in your amount until used to collect a character. They cannot be exchanged or used for other purposes, they also cannot be claimed for purchases made/duplicates received before the feature was released.

The totals of each bot shards can be checked by going into the new Bot Shop.

New Shop

An Autobot and Decepticon section has opened in the shop. Pressing the Autobots or Decepticons logos will lead you to the Bot shop for each faction.

This shop contains the complete lineup of all the 4-Star Bots and C.O.M.B.A.T. characters released with a quick preview of how much shards for that character you have and how many you need to unlock the 4-Star.

Clicking on a bot will take you to a purchase screen, with more information about the shards system, and a “GET NOW” button that becomes active after you get enough shards.

Pressing the “GET NOW” button will award the player with one 4-Star guaranteed crystal for that specific bot. The crystal will be available in the Space Bridge.

The Autobot and Decepticon shop lineup will be updated as we release new characters and C.O.M.B.A.T. Power Cores.

MIA Section

You can also unlock missing Bots from the Missing In Action section in the team menu, including 4-Star, 3-Star and even the 2-Star version for the completionist collectors (exchange is limited to 1 and not available for C.O.M.B.A.T. characters).

Tapping on the missing bot portrait will you get this screen. And pressing the “GET NOW” will give you a crystal that contains that star version of the bot.

FAQ

How many Character Shards are required to unlock each Star quality?
You will be required to collect 7,500 Character Shards for a 4-Star bot, 500 for a 3-Star bot and 100 for a 2-Star bot.