Souls of the Faultless

• WOTC Official Reminder Textofficial rules
  Defender — This creature can't attack.

• WWizards of the Coast2006-02-01
  Official Ruling
  If Souls of the Faultless is dealt combat damage in a Two-Headed Giant game, you may choose either member of the attacking team as the player who will lose life. The player you choose doesn't have to be the controller of a creature that dealt damage to Souls of the Faultless.
• WWizards of the Coast2006-02-01
  Official Ruling
  If Souls of the Faultless somehow attacks and is dealt combat damage, you will both gain and lose life when its ability resolves.

Rulings via Scryfall