With Rolf at 20 life and with a large ensemble of creatures, it’s unlikely that you’ll be able to best him in combat. As a result, it should be obvious that the Felidar Sovereign is your best route to victory in this case. You just need to figure out how to gain 29 life, and it’ll involve using Pulsemage Advocate’s ability. Be careful, though: Rolf has two mana open, and if you return either his Lightning Bolt or his Doom Blade, he won’t hesitate to crash your party with them.

1. Before Rolf’s turn ends, tap three forests to add GGG (two used as generic mana) and two plains to add WW (one used as generic mana) to your mana pool.
2. Spend 2 and remove a +1/+1 counter from Spike Feeder to activate its ability. Choose to put a +1/+1 counter on your Felidar Sovereign. Felidar Sovereign is now a 5/7 creature.
3. Spend G to cast Mutant’s Prey on Felidar Sovereign and Rolf’s Vampire Nighthawk, causing them to fight each other. Felidar Sovereign deals 5 damage to Vampire Nighthawk, causing you to gain 5 life; Vampire Nighthawk deals 2 damage to Felidar Sovereign, causing Rolf to gain 2 life. Both Felidar Sovereign and Vampire Nighthawk die (due to the Nighthawk’s Deathtouch ability). You are now at 16 life. Rolf is now at 22 life.
4. When Felidar Sovereign dies, your Mycoid Shepherd’s ability triggers. You gain 5 life. You are now at 21 life.
5. Spend 1W to cast Cursebreak on Rolf’s Fate Unraveler, destroying it. You gain 2 life. You are now at 23 life.
6. Because Rolf no longer controls any black permanents, he is forced to sacrifice his Lurebound Scarecrow.
7. Tap Pulsemage Advocate to activate its ability, returning Rolf’s Vampire Nighthawk, Fate Unraveler and Lurebound Scarecrow from his graveyard to his hand. Choose to return your Felidar Sovereign from your graveyard to the battlefield under your control.
8. Tap Lone Missionary, Oracle of Nectars, Spike Feeder, Mycoid Shepherd and Felidar Sovereign to cast Meditation Puzzle via its Convoke ability. You gain 8 life. You are now at 31 life.
9. Tap Plaguemaw Beast to activate its ability, sacrificing your Mycoid Shepherd. Choose to put a second +1/+1 counter on your Spike Feeder as a result of the Proliferate ability.
10. When you Mycoid Shepherd dies, its ability triggers, and you gain 5 life. You are now at 36 life.
11. Remove a +1/+1 counter from your Spike Feeder to activate its ability. You gain 2 life. You are now at 38 life.
12. Remove a +1/+1 counter from your Spike Feeder to activate its ability. You gain 2 life. You are now at 40 life.
13. Allow Rolf to end his turn. Rolf’s turn ends, and your turn begins.
14. At the beginning of your upkeep, Felidar Sovereign’s ability triggers, and you win the game.