Black Survival can be signed in with Google or Apple ID.
Therefore, if you have multiple Google or Apple ID, you can use multiple accounts on a single device.


On your device, go to 'Settings - Account - Add Account' and create new Google account.
Open Black Survival, in main lobby, go to 'Settings - Sync Device - Connected to Google' 
Pop up will appear with list of added accounts to your device.
Select the account you would like to sign in with on the list.

Go to!&page= and create new Apple ID. Next, go to Game Center, sign in with Apple ID, and open Black Survival

You can make a new account by making a new Steam account