Whenever you sacrifice a permanent, put a +1/+1 counter on Juri.
When Juri dies, it deals damage equal to its power to any target.
Juri grows every time you sacrifice a permanent, turning your sacrifice engine into a personal Voltron threat that can also be flung for a huge final blow. Turn to turn, you deploy cheap fodder, sacrifice it for value via aristocrats engines, stack counters on Juri, and either swing in or sacrifice/kill Juri to deal its power to a player or key creature. The deck doubles as an aristocrats damage machine, draining the table while Juri snowballs.
Built-in payoff for sacrifice synergies that most aristocrats decks already want
Cheap, two-mana commander that comes down early and scales all game
Juri's death trigger turns every board wipe or removal spell into reach/damage
Flexible win patterns: combat damage, fling effects, or drain
Strong in Rakdos colors with excellent removal and recursion
Relies on a steady stream of fodder to grow; runs out of gas without token generators
Counters are wiped if Juri is exiled rather than killed
Single-target death damage doesn't win against multiple opponents alone
Vulnerable to graveyard hate and removal of key sac outlets
Generates treasure on each death, fueling more sacrifices and ramp.
Mphen, the Lost
Token engine that refills fodder and reanimates after a wipe.
Add more free sacrifice outlets (Carrion Feeder, Viscera Seer) and token doublers to maximize counters per turn, plus Blood Artist effects to convert sacrifices into table-wide drain. Include ways to give Juri evasion or trample (Rancor, Whispersilk Cloak) and reliable recursion so its death trigger can be reused. Tighten the mana base and add tutors like Diabolic Intent to assemble engine pieces faster.