Nazgûl enters, triggering its first activated ability, causing the Ring to tempt you; choose Nazgûl as your Ring-bearer, making it legendary.
Nazgûl's second activated ability triggers, putting a +1/+1 counter on each Wraith you control.
Activate Goblin Bombardment by sacrificing Nazgûl.
Ratadrabik of Urborg triggers, creating a token copy of Nazgûl that's a 2/2 Zombie.
Resolve the ability from step 4, dealing 1 damage to any target.
Repeat from step 2.
This loop transforms a single Wraith into an endless cycle of sacrifice and rebirth, supercharged by the unique mechanics of the Ring. When you cast Nazgûl, it enters the battlefield and lets the Ring tempt you, making it legendary so that Ratadrabik of Urborg's static ability is ready to watch over it. Goblin Bombardment then provides the necessary outlet to sacrifice the Nazgûl, which triggers Ratadrabik of Urborg to spawn a fresh, non-legendary 2/2 Zombie copy. Because the token is also a Wraith, every iteration of the Ring tempting you adds another +1/+1 counter across your growing army while fueling an infinite storm count and endless damage.