To unlock the Deadly Encounter trophy in Mortal Kombat 11, you will need to perform 15 different fatalities. There is another trophy for performing 30 different fatalities:
You don't need to have unlocked the second fatality for each character in the Krypt to use them. There are trophies for performing two fatalities for each character, so you'll unlock this trophy along the way anyway if you are going for the platinum.
Mortal Kombat 11 Fatalities:Baraka:
Fatality One: (Close) Back > Down > Back >
Fatality Two: (Close) Back > Forward > Back >
Cassie Cage:
Fatality One: (Mid Distance) Down > Down > Forward >
Fatality Two: (Mid Distance) Back > Down > Down > Back >
Cetrion:
Fatality One: (Mid Distance) Back > Down > Forward > Down >
Fatality Two: (Mid Distance) Back > Down > Back >
D'Vorah:
Fatality One: (Close) Back > Forward > Back >
Fatality Two: (Mid Distance) Back > Down > Down >
Erron Black:
Fatality One: (Mid Distance) Down > Down > Down >
Fatality Two: Mid Distance) Down > Forward > Down >
Frost:
Fatality One: (Close) Forward > Back > Down >
Fatality Two: (Mid Distance) Back > Forward > Down > Forward >
Geras:
Fatality One: (Any Distance) Back > Down > Down >
Fatality Two: (Close) Down > Forward > Back >
Jacqui Briggs:
Fatality One: (Mid Distance) Forward > Back > Forward >
Fatality Two: (Mid Distance) Back > Forward > Back >
Jade:
Fatality One: (Any Distance) Down > Down > Forward > Down >
Fatality Two: (Close) Back > Forward > Down > Forward >
Jax Briggs:
Fatality One: (Close) Forward > Down > forward >
Fatality Two: (Close) Back > Forward > Back > Down >
Johnny Cage:
Fatality One: (Close) Forward > Back > Down > Down >
Fatality Two: (Close) Forward > Down > Forward >
Kabal:
Fatality One: (Mid Distance) Back > Forward > Down > Forward >
Fatality Two: (Close) Down > Down > Down >
Kano:
Fatality One: (Close) Forward > Down > Down >
Fatality Two: (Close) Back > Down > Forward >
Kitana:
Fatality One: (Mid Distance) Down > Down > Down > Down >
Fatality Two: (Mi Distance) Down > Back > Forward >
Kollector:
Fatality One: (Close) Down > Down > Down > Down >
Fatality Two: (Close) Down > Forard > Back >
Kotal Kahn:
Fatality One: (Close) Back > Down > Back >
Fatality Two: (Close) Back > Forward > Back > Forward >
Kung Lao:
Fatality One: (Close) Down > Forward > Back > Down >
Fatality Two: (Close) Down > Forward > Down >
Liu Kang:
Fatality One: (Close) Down > Back > Down > Forward >
Fatality Two: (Mid Distance) Back > Down > Back > Forward >
Noob Saibot:
Fatality One: (Mid Distance) Back > Forward > Back > Forward >
Fatality Two: (Close) Down > Down > Down >
Raiden:
Fatality One: (Mid Distance) Back > Down > Back >
Fatality Two: (Close) Down > Forward > Back >
Scorpion:
Fatality One: (Far) Back > Down > Down >
Fatality Two: (Far) Down > Forward > Back >
Skarlet:
Fatality One: (Mid Distance) Forward > Back > Down >
Fatality Two: (Mid Distance) Down > Down > Forward >
Sonya Blade:
Fatality One: (Mid Distance) Down > Forward > Back >
Fatality Two: (Close) Back > Forward > Down >
Sub-Zero:
Fatality One: (Mid Distance) Back > Forward > Back >
Fatality Two: (Mid Distance) Forward > Down > Forward >
Shao Kahn:
Fatality One: (Close) Back > Forward > Down > Down >
Fatality Two: (Close) Back > Forward > Back >