Attendant of Vraska

• WWizards of the Coast2018-10-05
  Official Ruling
  The amount of life gained is equal to Attendant of Vraska’s power as it last existed on the battlefield.
• WWizards of the Coast2018-10-05
  Official Ruling
  If you don’t control a Vraska planeswalker as Attendant of Vraska’s triggered ability resolves, possibly because Vraska left the battlefield at the same time as Attendant of Vraska, you won’t gain life.
• WWizards of the Coast2018-10-05
  Official Ruling
  If Attendant of Vraska’s power was negative, you don’t lose or gain life.

Rulings via Scryfall