Sarkhan Unbroken [Mythic Edition] 134 Twilight Imperium (Fourth Edition) is

Twilight Imperium (Fourth Edition) is a game of galactic conquest in which three to six players take on the role of one of seventeen factions vying for galactic domination through military might

You gain 3 life for each sacrificed creature

" —Whip Tongue

this was in fact the actual murderer

−2: Put a +1/+1 counter on each creature you control and a loyalty counter on each other planeswalker you control

Sarkhan Unbroken [Mythic Edition] 134 Twilight Imperium (Fourth Edition) isSet: Mythic Edition Type: Legendary Planeswalker Sarkhan Rarity: Mythic Cost: {2}{G}{U}{R} +1: Draw a card, then add one mana of any color. 2: Create a 4 4 red Dragon creature token with flying. 8: Search your library for any number of Dragon creature cards and put them onto the battlefield. Then shuffle your library.